htmldataprocessor.js

/**
 * @license Copyright (c) 2003-2023, CKSource Holding sp. z o.o. All rights reserved.
 * CKEditor 4 LTS ("Long Term Support") is available under the terms of the Extended Support Model.
 */

( function() {
	var removeReservedKeywords;

	/**
	 * Represents an HTML data processor, which is responsible for translating and
	 * transforming the editor data on input and output.
	 *
	 * @class
	 * @extends CKEDITOR.dataProcessor
	 * @constructor Creates an htmlDataProcessor class instance.
	 * @param {CKEDITOR.editor} editor
	 */
	CKEDITOR.htmlDataProcessor = function( editor ) {
		var dataFilter, htmlFilter,
			that = this;

		this.editor = editor;

		/**
		 * Data filter used when processing input by {@link #toHtml}.
		 *
		 * @property {CKEDITOR.htmlParser.filter}
		 */
		this.dataFilter = dataFilter = new CKEDITOR.htmlParser.filter();

		/**
		 * HTML filter used when processing output by {@link #toDataFormat}.
		 *
		 * @property {CKEDITOR.htmlParser.filter}
		 */
		this.htmlFilter = htmlFilter = new CKEDITOR.htmlParser.filter();

		/**
		 * The HTML writer used by this data processor to format the output.
		 *
		 * @property {CKEDITOR.htmlParser.basicWriter}
		 */
		this.writer = new CKEDITOR.htmlParser.basicWriter();

		dataFilter.addRules( defaultDataFilterRulesEditableOnly );
		dataFilter.addRules( defaultDataFilterRulesForAll, { applyToAll: true } );
		dataFilter.addRules( createBogusAndFillerRules( editor, 'data' ), { applyToAll: true } );
		htmlFilter.addRules( defaultHtmlFilterRulesEditableOnly );
		htmlFilter.addRules( defaultHtmlFilterRulesForAll, { applyToAll: true } );
		htmlFilter.addRules( createBogusAndFillerRules( editor, 'html' ), { applyToAll: true } );

		editor.on( 'toHtml', function( evt ) {
			var randomNumber = generateRandomNumber(),
				evtData = evt.data,
				data = evtData.dataValue,
				fixBodyTag;

			// Before we start protecting markup, make sure there are no externally injected
			// protection keywords.
			data = removeReservedKeywords( data );

			// The source data is already HTML, but we need to clean
			// it up and apply the filter.
			data = protectSource( data, editor, randomNumber );

			// Protect content of textareas. (https://dev.ckeditor.com/ticket/9995)
			// Do this before protecting attributes to avoid breaking:
			// <textarea><img src="..." /></textarea>
			data = protectElements( data, protectTextareaRegex );

			// Before anything, we must protect the URL attributes as the
			// browser may changing them when setting the innerHTML later in
			// the code.
			data = protectAttributes( data, randomNumber );

			// Protect elements than can't be set inside a DIV. E.g. IE removes
			// style tags from innerHTML. (https://dev.ckeditor.com/ticket/3710)
			data = protectElements( data, protectElementsRegex );

			// Certain elements has problem to go through DOM operation, protect
			// them by prefixing 'cke' namespace. (https://dev.ckeditor.com/ticket/3591)
			data = protectElementsNames( data );

			// All none-IE browsers ignore self-closed custom elements,
			// protecting them into open-close. (https://dev.ckeditor.com/ticket/3591)
			data = protectSelfClosingElements( data );

			// Compensate one leading line break after <pre> open as browsers
			// eat it up. (https://dev.ckeditor.com/ticket/5789)
			data = protectPreFormatted( data );

			// There are attributes which may execute JavaScript code inside fixBin.
			// Encode them greedily. They will be unprotected right after getting HTML from fixBin. (https://dev.ckeditor.com/ticket/10)
			data = protectInsecureAttributes( data, randomNumber );

			var fixBin = evtData.context || editor.editable().getName(),
				isPre;

			// Old IEs loose formats when load html into <pre>.
			if ( CKEDITOR.env.ie && CKEDITOR.env.version < 9 && fixBin == 'pre' ) {
				fixBin = 'div';
				data = '<pre>' + data + '</pre>';
				isPre = 1;
			}

			// Call the browser to help us fixing a possibly invalid HTML
			// structure.
			var el = editor.document.createElement( fixBin );
			// Add fake character to workaround IE comments bug. (https://dev.ckeditor.com/ticket/3801)
			el.setHtml( 'a' + data );
			data = el.getHtml().substr( 1 );

			// Restore shortly protected attribute names.
			data = data.replace( new RegExp( 'data-cke-' + randomNumber + '-', 'ig' ), '' );

			isPre && ( data = data.replace( /^<pre>|<\/pre>$/gi, '' ) );

			// Unprotect "some" of the protected elements at this point.
			data = unprotectElementNames( data );

			data = unprotectElements( data );

			// Restore the comments that have been protected, in this way they
			// can be properly filtered.
			data = unprotectRealComments( data );

			if ( evtData.fixForBody === false ) {
				fixBodyTag = false;
			} else {
				fixBodyTag = getFixBodyTag( evtData.enterMode, editor.config.autoParagraph );
			}

			// Now use our parser to make further fixes to the structure, as
			// well as apply the filter.
			data = CKEDITOR.htmlParser.fragment.fromHtml( data, evtData.context, fixBodyTag );

			// The empty root element needs to be fixed by adding 'p' or 'div' into it.
			// This avoids the need to create that element on the first focus (https://dev.ckeditor.com/ticket/12630).
			if ( fixBodyTag ) {
				fixEmptyRoot( data, fixBodyTag );
			}

			evtData.dataValue = data;
		}, null, null, 5 );

		// Filter incoming "data".
		// Add element filter before htmlDataProcessor.dataFilter when purifying input data to correct html.
		editor.on( 'toHtml', function( evt ) {
			if ( evt.data.filter.applyTo( evt.data.dataValue, true, evt.data.dontFilter, evt.data.enterMode ) )
				editor.fire( 'dataFiltered' );
		}, null, null, 6 );

		editor.on( 'toHtml', function( evt ) {
			evt.data.dataValue.filterChildren( that.dataFilter, true );
		}, null, null, 10 );

		editor.on( 'toHtml', function( evt ) {
			var evtData = evt.data,
				data = evtData.dataValue,
				writer = new CKEDITOR.htmlParser.basicWriter();

			data.writeChildrenHtml( writer );
			data = writer.getHtml( true );

			// Protect the real comments again.
			evtData.dataValue = protectRealComments( data );
		}, null, null, 15 );


		editor.on( 'toDataFormat', function( evt ) {
			var data = evt.data.dataValue;

			// https://dev.ckeditor.com/ticket/10854 - we need to strip leading blockless <br> which FF adds
			// automatically when editable contains only non-editable content.
			// We do that for every browser (so it's a constant behavior) and
			// not in BR mode, in which chance of valid leading blockless <br> is higher.
			if ( evt.data.enterMode != CKEDITOR.ENTER_BR )
				data = data.replace( /^<br *\/?>/i, '' );

			evt.data.dataValue = CKEDITOR.htmlParser.fragment.fromHtml(
				data, evt.data.context, getFixBodyTag( evt.data.enterMode, editor.config.autoParagraph ) );
		}, null, null, 5 );

		editor.on( 'toDataFormat', function( evt ) {
			evt.data.dataValue.filterChildren( that.htmlFilter, true );
		}, null, null, 10 );

		// Transform outcoming "data".
		// Add element filter after htmlDataProcessor.htmlFilter when preparing output data HTML.
		editor.on( 'toDataFormat', function( evt ) {
			evt.data.filter.applyTo( evt.data.dataValue, false, true );
		}, null, null, 11 );

		editor.on( 'toDataFormat', function( evt ) {
			var data = evt.data.dataValue,
				writer = that.writer;

			writer.reset();
			data.writeChildrenHtml( writer );
			data = writer.getHtml( true );

			// Restore those non-HTML protected source. (https://dev.ckeditor.com/ticket/4475,https://dev.ckeditor.com/ticket/4880)
			data = unprotectRealComments( data );
			data = unprotectSource( data, editor );

			evt.data.dataValue = data;
		}, null, null, 15 );
	};

	CKEDITOR.htmlDataProcessor.prototype = {
		/**
		 * Processes the (potentially malformed) input HTML to a purified form which
		 * is suitable for using in the WYSIWYG editable.
		 *
		 * This method fires the {@link CKEDITOR.editor#toHtml} event which makes it possible
		 * to hook into the process at various stages.
		 *
		 * **Note:** Since CKEditor 4.3.0 the signature of this method changed and all options
		 * are now grouped in one `options` object. Previously `context`, `fixForBody` and `dontFilter`
		 * were passed separately.
		 *
		 * @param {String} data The raw data.
		 * @param {Object} [options] The options object.
		 * @param {String} [options.context] The tag name of a context element within which
		 * the input is to be processed, defaults to the editable element.
		 * If `null` is passed, then data will be parsed without context (as children of {@link CKEDITOR.htmlParser.fragment}).
		 * See {@link CKEDITOR.htmlParser.fragment#fromHtml} for more details.
		 * @param {Boolean} [options.fixForBody=true] Whether to trigger the auto paragraph for non-block content.
		 * @param {CKEDITOR.filter} [options.filter] When specified, instead of using the {@link CKEDITOR.editor#filter main filter},
		 * the passed instance will be used to filter the content.
		 * @param {Boolean} [options.dontFilter] Do not filter data with {@link CKEDITOR.filter} (note: transformations
		 * will still be applied).
		 * @param {Number} [options.enterMode] When specified, it will be used instead of the {@link CKEDITOR.editor#enterMode main enterMode}.
		 * @param {Boolean} [options.protectedWhitespaces] Indicates that content was wrapped with `<span>` elements to preserve
		 * leading and trailing whitespaces. Option used by the {@link CKEDITOR.editor#method-insertHtml} method.
		 * @returns {String}
		 */
		toHtml: function( data, options, fixForBody, dontFilter ) {
			var editor = this.editor,
				context, filter, enterMode, protectedWhitespaces;

			// Typeof null == 'object', so check truthiness of options too.
			if ( options && typeof options == 'object' ) {
				context = options.context;
				fixForBody = options.fixForBody;
				dontFilter = options.dontFilter;
				filter = options.filter;
				enterMode = options.enterMode;
				protectedWhitespaces = options.protectedWhitespaces;
			}
			// Backward compatibility. Since CKEDITOR 4.3.0 every option was a separate argument.
			else {
				context = options;
			}

			// Fall back to the editable as context if not specified.
			if ( !context && context !== null )
				context = editor.editable().getName();

			return editor.fire( 'toHtml', {
				dataValue: data,
				context: context,
				fixForBody: fixForBody,
				dontFilter: dontFilter,
				filter: filter || editor.filter,
				enterMode: enterMode || editor.enterMode,
				protectedWhitespaces: protectedWhitespaces
			} ).dataValue;
		},

		/**
		 * See {@link CKEDITOR.dataProcessor#toDataFormat}.
		 *
		 * This method fires the {@link CKEDITOR.editor#toDataFormat} event which makes it possible
		 * to hook into the process at various stages.
		 *
		 * @param {String} html
		 * @param {Object} [options] The options object.
		 * @param {String} [options.context] The tag name of the context element within which
		 * the input is to be processed, defaults to the editable element.
		 * @param {CKEDITOR.filter} [options.filter] When specified, instead of using the {@link CKEDITOR.editor#filter main filter},
		 * the passed instance will be used to apply content transformations to the content.
		 * @param {Number} [options.enterMode] When specified, it will be used instead of the {@link CKEDITOR.editor#enterMode main enterMode}.
		 * @returns {String}
		 */
		toDataFormat: function( html, options ) {
			var context, filter, enterMode;

			// Do not shorten this to `options && options.xxx`, because
			// falsy `options` will be passed instead of undefined.
			if ( options ) {
				context = options.context;
				filter = options.filter;
				enterMode = options.enterMode;
			}

			// Fall back to the editable as context if not specified.
			if ( !context && context !== null )
				context = this.editor.editable().getName();

			return this.editor.fire( 'toDataFormat', {
				dataValue: html,
				filter: filter || this.editor.filter,
				context: context,
				enterMode: enterMode || this.editor.enterMode
			} ).dataValue;
		},

		/**
		 * @since 4.16.1
		 * @private
		 * @param {String} data
		 */
		protectSource: function( data ) {
			return protectSource( data, this.editor );
		},

		/**
		 * @since 4.16.1
		 * @private
		 * @param {String} html
		 */
		unprotectSource: function( html ) {
			return unprotectSource( html, this.editor );
		},

		/**
		 * @since 4.16.2
		 * @private
		 * @param {String} html
		 */
		unprotectRealComments: function( html ) {
			return unprotectRealComments( html );
		}
	};

	// Produce a set of filtering rules that handles bogus and filler node at the
	// end of block/pseudo block, in the following consequence:
	// 1. elements:<block> - this filter removes any bogus node, then check
	// if it's an empty block that requires a filler.
	// 2. elements:<br> - After cleaned with bogus, this filter checks the real
	// line-break BR to compensate a filler after it.
	//
	// Terms definitions:
	// filler: An element that's either <BR> or &NBSP; at the end of block that established line height.
	// bogus: Whenever a filler is proceeded with inline content, it becomes a bogus which is subjected to be removed.
	//
	// Various forms of the filler:
	// In output HTML: Filler should be consistently &NBSP; <BR> at the end of block is always considered as bogus.
	// In Wysiwyg HTML: Browser dependent - see env.needsBrFiller. Either BR for when needsBrFiller is true, or &NBSP; otherwise.
	// <BR> is NEVER considered as bogus when needsBrFiller is true.
	function createBogusAndFillerRules( editor, type ) {
		function createFiller( isOutput ) {
			return isOutput || CKEDITOR.env.needsNbspFiller ?
				new CKEDITOR.htmlParser.text( '\xa0' ) :
				new CKEDITOR.htmlParser.element( 'br', { 'data-cke-bogus': 1 } );
		}

		// This text block filter, remove any bogus and create the filler on demand.
		function blockFilter( isOutput, fillEmptyBlock ) {

			return function( block ) {
				// DO NOT apply the filler if it's a fragment node.
				if ( block.type == CKEDITOR.NODE_DOCUMENT_FRAGMENT )
					return;

				cleanBogus( block );

				// Add fillers to input (always) and to output (if fillEmptyBlock is ok with that).
				var shouldFillBlock = !isOutput ||
					( typeof fillEmptyBlock == 'function' ? fillEmptyBlock( block ) : fillEmptyBlock ) !== false;

				if ( shouldFillBlock && isEmptyBlockNeedFiller( block ) ) {
					block.add( createFiller( isOutput ) );
				}
			};
		}

		// Append a filler right after the last line-break BR, found at the end of block.
		function brFilter( isOutput ) {
			return function( br ) {
				// DO NOT apply the filer if parent's a fragment node.
				if ( br.parent.type == CKEDITOR.NODE_DOCUMENT_FRAGMENT )
					return;

				var attrs = br.attributes;
				// Dismiss BRs that are either bogus or eol marker.
				if ( 'data-cke-bogus' in attrs || 'data-cke-eol' in attrs ) {
					delete attrs [ 'data-cke-bogus' ];
					return;
				}

				// Judge the tail line-break BR, and to insert bogus after it.
				var next = getNext( br ), previous = getPrevious( br );

				if ( !next && isBlockBoundary( br.parent ) )
					append( br.parent, createFiller( isOutput ) );
				else if ( isBlockBoundary( next ) && previous && !isBlockBoundary( previous ) )
					createFiller( isOutput ).insertBefore( next );
			};
		}

		// Determinate whether this node is potentially a bogus node.
		function maybeBogus( node, atBlockEnd ) {

			// BR that's not from IE<11 DOM, except for a EOL marker.
			if ( !( isOutput && !CKEDITOR.env.needsBrFiller ) &&
					node.type == CKEDITOR.NODE_ELEMENT && node.name == 'br' &&
					!node.attributes[ 'data-cke-eol' ] ) {
				return true;
			}

			var match;

			// NBSP, possibly.
			if ( node.type == CKEDITOR.NODE_TEXT && ( match = node.value.match( tailNbspRegex ) ) ) {
				// We need to separate tail NBSP out of a text node, for later removal.
				if ( match.index ) {
					( new CKEDITOR.htmlParser.text( node.value.substring( 0, match.index ) ) ).insertBefore( node );
					node.value = match[ 0 ];
				}

				// From IE<11 DOM, at the end of a text block, or before block boundary.
				if ( !CKEDITOR.env.needsBrFiller && isOutput && ( !atBlockEnd || node.parent.name in textBlockTags ) )
					return true;

				// From the output.
				if ( !isOutput ) {
					var previous = node.previous;

					// Following a line-break at the end of block.
					if ( previous && previous.name == 'br' )
						return true;

					// Or a single NBSP between two blocks.
					if ( !previous || isBlockBoundary( previous ) )
						return true;
				}
			}

			return false;
		}

		// Removes all bogus inside of this block, and to convert fillers into the proper form.
		function cleanBogus( block ) {
			var bogus = [];
			var last = getLast( block ), node, previous;

			if ( last ) {
				// Check for bogus at the end of this block.
				// e.g. <p>foo<br /></p>
				maybeBogus( last, 1 ) && bogus.push( last );

				while ( last ) {
					// Check for bogus at the end of any pseudo block contained.
					if ( isBlockBoundary( last ) && ( node = getPrevious( last ) ) && maybeBogus( node ) ) {
						// Bogus must have inline proceeding, instead single BR between two blocks,
						// is considered as filler, e.g. <hr /><br /><hr />
						if ( ( previous = getPrevious( node ) ) && !isBlockBoundary( previous ) )
							bogus.push( node );
						// Convert the filler into appropriate form.
						else {
							createFiller( isOutput ).insertAfter( node );
							node.remove();
						}
					}

					last = last.previous;
				}
			}

			// Now remove all bogus collected from above.
			for ( var i = 0 ; i < bogus.length ; i++ )
				bogus[ i ].remove();
		}

		// Judge whether it's an empty block that requires a filler node.
		function isEmptyBlockNeedFiller( block ) {

			// DO NOT fill empty editable in IE<11.
			if ( !isOutput && !CKEDITOR.env.needsBrFiller && block.type == CKEDITOR.NODE_DOCUMENT_FRAGMENT )
				return false;

			// 1. For IE version >=8,  empty blocks are displayed correctly themself in wysiwiyg;
			// 2. For the rest, at least table cell and list item need no filler space. (https://dev.ckeditor.com/ticket/6248)
			if ( !isOutput && !CKEDITOR.env.needsBrFiller &&
				( document.documentMode > 7 ||
					block.name in CKEDITOR.dtd.tr ||
					block.name in CKEDITOR.dtd.$listItem ) ) {
				return false;
			}

			var last = getLast( block );
			return !last || block.name == 'form' && last.name == 'input' ;
		}

		var rules = { elements: {} },
			isOutput = type == 'html',
			textBlockTags = CKEDITOR.tools.extend( {}, blockLikeTags );

		// Build the list of text blocks.
		for ( var i in textBlockTags ) {
			if ( !( '#' in dtd[ i ] ) )
				delete textBlockTags[ i ];
		}

		for ( i in textBlockTags )
			rules.elements[ i ] = blockFilter( isOutput, editor.config.fillEmptyBlocks );

		// Editable element has to be checked separately.
		rules.root = blockFilter( isOutput, false );
		rules.elements.br = brFilter( isOutput );
		return rules;
	}

	function getFixBodyTag( enterMode, autoParagraph ) {
		return ( enterMode != CKEDITOR.ENTER_BR && autoParagraph !== false ) ? enterMode == CKEDITOR.ENTER_DIV ? 'div' : 'p' : false;
	}

	// Regex to scan for &nbsp; at the end of blocks, which are actually placeholders.
	// Safari transforms the &nbsp; to \xa0. (https://dev.ckeditor.com/ticket/4172)
	var tailNbspRegex = /(?:&nbsp;|\xa0)$/;

	var protectedSourceMarker = '{cke_protected}';

	function getLast( node ) {
		var last = node.children[ node.children.length - 1 ];
		while ( last && isEmpty( last ) )
			last = last.previous;
		return last;
	}

	function getNext( node ) {
		var next = node.next;
		while ( next && isEmpty( next ) )
			next = next.next;
		return next;
	}

	function getPrevious( node ) {
		var previous = node.previous;
		while ( previous && isEmpty( previous ) )
			previous = previous.previous;
		return previous;
	}

	// Judge whether the node is an ghost node to be ignored, when traversing.
	function isEmpty( node ) {
		return node.type == CKEDITOR.NODE_TEXT &&
			!CKEDITOR.tools.trim( node.value ) ||
			node.type == CKEDITOR.NODE_ELEMENT &&
			node.attributes[ 'data-cke-bookmark' ];
	}

	// Judge whether the node is a block-like element.
	function isBlockBoundary( node ) {
		return node &&
			( node.type == CKEDITOR.NODE_ELEMENT && node.name in blockLikeTags ||
			node.type == CKEDITOR.NODE_DOCUMENT_FRAGMENT );
	}

	function append( parent, node ) {
		var last = parent.children[ parent.children.length - 1 ];
		parent.children.push( node );
		node.parent = parent;
		if ( last ) {
			last.next = node;
			node.previous = last;
		}
	}

	function getNodeIndex( node ) {
		return node.parent ? node.getIndex() : -1;
	}

	var dtd = CKEDITOR.dtd,
		// Define orders of table elements.
		tableOrder = [ 'caption', 'colgroup', 'col', 'thead', 'tfoot', 'tbody' ],
		// List of all block elements.
		blockLikeTags = CKEDITOR.tools.extend( {}, dtd.$blockLimit, dtd.$block );

	//
	// DATA filter rules ------------------------------------------------------
	//

	var defaultDataFilterRulesEditableOnly = {
		elements: {
			input: protectReadOnly,
			textarea: protectReadOnly
		}
	};

	// These rules will also be applied to non-editable content.
	var defaultDataFilterRulesForAll = {
		attributeNames: [
			// Event attributes (onXYZ) must not be directly set. They can become
			// active in the editing area (IE|WebKit).
			[ ( /^on/ ), 'data-cke-pa-on' ],

			// Prevent iframe's srcdoc attribute from being evaluated in the editable.
			[ ( /^srcdoc/ ), 'data-cke-pa-srcdoc' ],

			// Don't let some old expando enter editor. Concerns only IE8,
			// but for consistency remove on all browsers.
			[ ( /^data-cke-expando$/ ), '' ]
		],

		elements: {
			// Prevent iframe's src attribute with javascript code or data protocol from being evaluated in the editable.
			iframe: function( element ) {
				if ( element.attributes && element.attributes.src ) {

					var src = element.attributes.src.toLowerCase().replace( /[^a-z]/gi, '' );
					if ( src.indexOf( 'javascript' ) === 0 || src.indexOf( 'data' ) === 0 ) {
						element.attributes[ 'data-cke-pa-src' ] = element.attributes.src;
						delete element.attributes.src;
					}
				}
			}
		}
	};

	// Disable form elements editing mode provided by some browsers. (https://dev.ckeditor.com/ticket/5746)
	function protectReadOnly( element ) {
		var attrs = element.attributes;

		// We should flag that the element was locked by our code so
		// it'll be editable by the editor functions (https://dev.ckeditor.com/ticket/6046).
		if ( attrs.contenteditable != 'false' )
			attrs[ 'data-cke-editable' ] = attrs.contenteditable ? 'true' : 1;

		attrs.contenteditable = 'false';
	}

	//
	// HTML filter rules ------------------------------------------------------
	//

	var defaultHtmlFilterRulesEditableOnly = {
		elements: {
			embed: function( element ) {
				var parent = element.parent;

				// If the <embed> is child of a <object>, copy the width
				// and height attributes from it.
				if ( parent && parent.name == 'object' ) {
					var parentWidth = parent.attributes.width,
						parentHeight = parent.attributes.height;
					if ( parentWidth )
						element.attributes.width = parentWidth;
					if ( parentHeight )
						element.attributes.height = parentHeight;
				}
			},

			// Remove empty link but not empty anchor. (https://dev.ckeditor.com/ticket/3829, https://dev.ckeditor.com/ticket/13516)
			a: function( element ) {
				var attrs = element.attributes;

				if ( !( element.children.length || attrs.name || attrs.id || element.attributes[ 'data-cke-saved-name' ] ) )
					return false;
			}
		}
	};

	// These rules will also be applied to non-editable content.
	var defaultHtmlFilterRulesForAll = {
		elementNames: [
			// Remove the "cke:" namespace prefix.
			[ ( /^cke:/ ), '' ],

			// Ignore <?xml:namespace> tags.
			[ ( /^\?xml:namespace$/ ), '' ]
		],

		attributeNames: [
			// Attributes saved for changes and protected attributes.
			[ ( /^data-cke-(saved|pa)-/ ), '' ],

			// All "data-cke-" attributes are to be ignored.
			[ ( /^data-cke-.*/ ), '' ],

			[ 'hidefocus', '' ]
		],

		elements: {
			$: function( element ) {
				var attribs = element.attributes;

				if ( attribs ) {
					// Elements marked as temporary are to be ignored.
					if ( attribs[ 'data-cke-temp' ] )
						return false;

					// Remove duplicated attributes - https://dev.ckeditor.com/ticket/3789.
					var attributeNames = [ 'name', 'href', 'src' ],
						savedAttributeName;
					for ( var i = 0; i < attributeNames.length; i++ ) {
						savedAttributeName = 'data-cke-saved-' + attributeNames[ i ];
						savedAttributeName in attribs && ( delete attribs[ attributeNames[ i ] ] );
					}
				}

				return element;
			},

			// The contents of table should be in correct order (https://dev.ckeditor.com/ticket/4809).
			table: function( element ) {
				// Clone the array as it would become empty during the sort call.
				var children = element.children.slice( 0 );

				children.sort( function( node1, node2 ) {
					var index1, index2;

					// Compare in the predefined order.
					if ( node1.type == CKEDITOR.NODE_ELEMENT && node2.type == node1.type ) {
						index1 = CKEDITOR.tools.indexOf( tableOrder, node1.name );
						index2 = CKEDITOR.tools.indexOf( tableOrder, node2.name );
					}

					// Make sure the sort is stable, if no order can be established above.
					if ( !( index1 > -1 && index2 > -1 && index1 != index2 ) ) {
						index1 = getNodeIndex( node1 );
						index2 = getNodeIndex( node2 );
					}

					return index1 > index2 ? 1 : -1;
				} );
			},

			// Restore param elements into self-closing.
			param: function( param ) {
				param.children = [];
				param.isEmpty = true;
				return param;
			},

			// Remove dummy span in webkit.
			span: function( element ) {
				if ( element.attributes[ 'class' ] == 'Apple-style-span' )
					delete element.name;
			},

			html: function( element ) {
				delete element.attributes.contenteditable;
				delete element.attributes[ 'class' ];
			},

			body: function( element ) {
				delete element.attributes.spellcheck;
				delete element.attributes.contenteditable;
			},

			style: function( element ) {
				var child = element.children[ 0 ];
				if ( child && child.value )
					child.value = CKEDITOR.tools.trim( child.value );

				if ( !element.attributes.type )
					element.attributes.type = 'text/css';
			},

			title: function( element ) {
				var titleText = element.children[ 0 ];

				// Append text-node to title tag if not present (i.e. non-IEs) (https://dev.ckeditor.com/ticket/9882).
				!titleText && append( element, titleText = new CKEDITOR.htmlParser.text() );

				// Transfer data-saved title to title tag.
				titleText.value = element.attributes[ 'data-cke-title' ] || '';
			},

			input: unprotectReadyOnly,
			textarea: unprotectReadyOnly
		},

		attributes: {
			'class': function( value ) {
				// Remove all class names starting with "cke_".
				return CKEDITOR.tools.ltrim( value.replace( /(?:^|\s+)cke_[^\s]*/g, '' ) ) || false;
			}
		}
	};

	if ( CKEDITOR.env.ie ) {
		// IE outputs style attribute in capital letters. We should convert
		// them back to lower case, while not hurting the values (https://dev.ckeditor.com/ticket/5930)
		defaultHtmlFilterRulesForAll.attributes.style = function( value ) {
			return value.replace( /(^|;)([^\:]+)/g, function( match ) {
				return match.toLowerCase();
			} );
		};
	}

	// Disable form elements editing mode provided by some browsers. (https://dev.ckeditor.com/ticket/5746)
	function unprotectReadyOnly( element ) {
		var attrs = element.attributes;
		switch ( attrs[ 'data-cke-editable' ] ) {
			case 'true':
				attrs.contenteditable = 'true';
				break;
			case '1':
				delete attrs.contenteditable;
				break;
		}
	}

	//
	// Preprocessor filters ---------------------------------------------------
	//

	var protectElementRegex = /<(a|area|img|input|source)\b([^>]*)>/gi,
		// Be greedy while looking for protected attributes. This will let us avoid an unfortunate
		// situation when "nested attributes", which may appear valid, are also protected.
		// I.e. if we consider the following HTML:
		//
		// 	<img data-x="&lt;a href=&quot;X&quot;" />
		//
		// then the "non-greedy match" returns:
		//
		// 	'href' => '&quot;X&quot;' // It's wrong! Href is not an attribute of <img>.
		//
		// while greedy match returns:
		//
		// 	'data-x' => '&lt;a href=&quot;X&quot;'
		//
		// which, can be easily filtered out (https://dev.ckeditor.com/ticket/11508).
		protectAttributeRegex = /([\w-:]+)\s*=\s*(?:(?:"[^"]*")|(?:'[^']*')|(?:[^ "'>]+))/gi,
		protectAttributeNameRegex = /^(href|src|name)$/i;

		// Note: we use lazy star '*?' to prevent eating everything up to the last occurrence of </style> or </textarea>.
	var protectElementsRegex = /(?:<style(?=[ >])[^>]*>[\s\S]*?<\/style>)|(?:<(:?link|meta|base)[^>]*>)/gi,
		protectTextareaRegex = /(<textarea(?=[ >])[^>]*>)([\s\S]*?)(?:<\/textarea>)/gi,
		encodedElementsRegex = /<cke:encoded>([^<]*)<\/cke:encoded>/gi;

		// Element name should be followed by space or closing angle bracket '>' to not protect custom tags (#988).
	var protectElementNamesRegex = /(<\/?)((?:object|embed|param|html|body|head|title)([\s][^>]*)?>)/gi,
		unprotectElementNamesRegex = /(<\/?)cke:((?:html|body|head|title)[^>]*>)/gi;

	var protectSelfClosingRegex = /<cke:(param|embed)([^>]*?)\/?>(?!\s*<\/cke:\1)/gi;

	function protectAttributes( html, randomNumber ) {
		return html.replace( protectElementRegex, function( element, tag, attributes ) {
			return '<' + tag + attributes.replace( protectAttributeRegex, function( fullAttr, attrName ) {
				// Avoid corrupting the inline event attributes (https://dev.ckeditor.com/ticket/7243).
				// We should not rewrite the existed protected attributes, e.g. clipboard content from editor. (https://dev.ckeditor.com/ticket/5218)
				if ( protectAttributeNameRegex.test( attrName ) && attributes.indexOf( 'data-cke-saved-' + attrName ) == -1 )
					return ' data-cke-saved-' + fullAttr + ' data-cke-' + randomNumber + '-' + fullAttr;

				return fullAttr;
			} ) + '>';
		} );
	}

	function protectElements( html, regex ) {
		return html.replace( regex, function( match, tag, content ) {
			// Encode < and > in textarea because this won't be done by a browser, since
			// textarea will be protected during passing data through fix bin.
			if ( match.indexOf( '<textarea' ) === 0 )
				match = tag + unprotectRealComments( content ).replace( /</g, '&lt;' ).replace( />/g, '&gt;' ) + '</textarea>';

			return '<cke:encoded>' + encodeURIComponent( match ) + '</cke:encoded>';
		} );
	}

	function unprotectElements( html ) {
		return html.replace( encodedElementsRegex, function( match, encoded ) {
			return decodeURIComponent( encoded );
		} );
	}

	function protectElementsNames( html ) {
		return html.replace( protectElementNamesRegex, '$1cke:$2' );
	}

	function unprotectElementNames( html ) {
		return html.replace( unprotectElementNamesRegex, '$1$2' );
	}

	function protectSelfClosingElements( html ) {
		return html.replace( protectSelfClosingRegex, '<cke:$1$2></cke:$1>' );
	}

	function protectPreFormatted( html ) {
		return html.replace( /(<pre\b[^>]*>)(\r\n|\n)/g, '$1$2$2' );
	}

	function protectRealComments( html ) {
		return html.replace( /<!--(?!{cke_protected})[\s\S]+?-->/g, function( match ) {
			return '<!--' + protectedSourceMarker +
				'{C}' +
				encodeURIComponent( match ).replace( /--/g, '%2D%2D' ) +
				'-->';
		} );
	}

	// Replace all "on\w{3,}" strings which are not:
	// * opening tags - e.g. `<onfoo`,
	// * closing tags - e.g. </onfoo> (tested in "false positive 1"),
	// * part of other attribute - e.g. `data-onfoo` or `fonfoo`.
	function protectInsecureAttributes( html, randomNumber ) {
		return html.replace( /([^a-z0-9<\-])(on\w{3,})(?!>)/gi, '$1data-cke-' + randomNumber + '-$2' );
	}

	function unprotectRealComments( html ) {
		return html.replace( /<!--\{cke_protected\}\{C\}([\s\S]+?)-->/g, function( match, data ) {
			return decodeURIComponent( data );
		} );
	}

	function unprotectSource( html, editor ) {
		var store = editor._.dataStore;

		return html.replace( /<!--\{cke_protected\}([\s\S]+?)-->/g, function( match, data ) {
			return decodeURIComponent( data );
		} ).replace( /\{cke_protected_(\d+)\}/g, function( match, id ) {
			return store && store[ id ] || '';
		} );
	}

	function protectSource( data, editor, randomNumber ) {
		var protectedHtml = [],
			protectRegexes = editor.config.protectedSource,
			store = editor._.dataStore || ( editor._.dataStore = { id: 1 } ),
			tempRegex = new RegExp('<\\!--\\{cke_temp_' + randomNumber + '(comment)?\\}(\\d*?)-->', 'g' );

		var regexes = [
			// Script tags will also be forced to be protected, otherwise
			// IE will execute them.
			( /<script[\s\S]*?(<\/script>|$)/gi ),

			// <noscript> tags (get lost in IE and messed up in FF).
			/<noscript[\s\S]*?<\/noscript>/gi,

			// Avoid meta tags being stripped (https://dev.ckeditor.com/ticket/8117).
			/<meta[\s\S]*?\/?>/gi
		].concat( protectRegexes );

		// First of any other protection, we must protect all comments
		// to avoid loosing them (of course, IE related).
		// Note that we use a different tag for comments, as we need to
		// transform them when applying filters.
		data = data.replace( ( /<!--[\s\S]*?-->/g ), function( match ) {
			return '<!--{cke_temp_' + randomNumber + 'comment}' + ( protectedHtml.push( match ) - 1 ) + '-->';
		} );

		for ( var i = 0; i < regexes.length; i++ ) {
			data = data.replace( regexes[ i ], function( match ) {
				match = match.replace( tempRegex, // There could be protected source inside another one. (https://dev.ckeditor.com/ticket/3869).
				function( $, isComment, id ) {
					return protectedHtml[ id ];
				} );

				// Avoid protecting over protected, e.g. /\{.*?\}/
				return ( tempRegex ).test( match ) ? match : '<!--{cke_temp_' + randomNumber + '}' +
					( protectedHtml.push( match ) - 1 ) + '-->';
			} );
		}
		data = data.replace( tempRegex, function( $, isComment, id ) {
			return '<!--' + protectedSourceMarker +
				( isComment ? '{C}' : '' ) +
				encodeURIComponent( protectedHtml[ id ] ).replace( /--/g, '%2D%2D' ) +
				'-->';
		} );

		// Different protection pattern is used for those that
		// live in attributes to avoid from being HTML encoded.
		// Why so serious? See https://dev.ckeditor.com/ticket/9205, https://dev.ckeditor.com/ticket/8216, https://dev.ckeditor.com/ticket/7805,
		// https://dev.ckeditor.com/ticket/11754, https://dev.ckeditor.com/ticket/11846.
		data = data.replace( /<\w+(?:\s+(?:(?:[^\s=>]+\s*=\s*(?:[^'"\s>]+|'[^']*'|"[^"]*"))|[^\s=\/>]+))+\s*\/?>/g, function( match ) {
			return match.replace( /<!--\{cke_protected\}([^>]*)-->/g, function( match, data ) {
				store[ store.id ] = decodeURIComponent( data );
				return '{cke_protected_' + ( store.id++ ) + '}';
			} );
		} );

		// This RegExp searches for innerText in all the title/iframe/textarea elements.
		// This is because browser doesn't allow HTML in these elements, that's why we can't
		// nest comments in there. (https://dev.ckeditor.com/ticket/11223)
		data = data.replace( /<(title|iframe|textarea)([^>]*)>([\s\S]*?)<\/\1>/g, function( match, tagName, tagAttributes, innerText ) {
			return '<' + tagName + tagAttributes + '>' + unprotectSource( unprotectRealComments( innerText ), editor ) + '</' + tagName + '>';
		} );

		return data;
	}

	// Creates a block if the root element is empty.
	function fixEmptyRoot( root, fixBodyTag ) {
		if ( !root.children.length && CKEDITOR.dtd[ root.name ][ fixBodyTag ] ) {
			var fixBodyElement = new CKEDITOR.htmlParser.element( fixBodyTag );
			root.add( fixBodyElement );
		}
	}

	// Removes reserved htmldataprocessor keywords ensuring that they are only used internally.
	// This function produces very complicated regex code. Using IIFE ensures that the regex
	// is build only once for this module.
	removeReservedKeywords = ( function() {
		var regexes = [
			createEncodedKeywordRegex(),
			createSourceKeywordRegex(),
			createIncorrectCommentRegex()
		];

		return function( data ) {
			while( isContentMatchingAnyPattern( regexes, data ) ) {
				data = removeMatchingContent( regexes, data );
			}

			return data;
		};

		function isContentMatchingAnyPattern( regexes, data ) {
			for ( var i = 0; i < regexes.length; i++ ) {
				var regex = regexes[ i ];

				regex.lastIndex = 0;

				if ( regex.test( data ) ) {
					return true;
				}
			}

			return false;
		}

		function removeMatchingContent( regexes, data ) {
			for ( var i = 0; i < regexes.length; i++ ) {
				data = data.replace( regexes[ i ], '' );
			}
			return data;
		}

		function createIncorrectCommentRegex() {
			return /<!(?:\s*-\s*){2,3}!?\s*>/g;
		}

		// Produces regex matching `cke:encoded` element.
		function createEncodedKeywordRegex() {
			return new RegExp( '(' +
				// Create closed element regex i.e `<cke:encoded>xxx</cke:encoded>`.
				createEncodedRegex( '<cke:encoded>' ) +
				'(.*?)' +
				createEncodedRegex( '</cke:encoded>' ) +
				')|(' +
				// Create unclosed element regex i.e `<cke:encoded>xxx` or `xxx</cke:encoded>` to make sure that
				// element won't be closed by HTML parser and matched by `unprotectElements` function.
				createEncodedRegex( '<' ) +
				createEncodedRegex( '/' ) + '?' +
				createEncodedRegex( 'cke:encoded>' ) +
				')', 'gi' );
		}

		// Produces regex matching `{cke_protected}` and `{cke_protected_id}` keywords.
		function createSourceKeywordRegex() {
			return new RegExp( '((' +
				createEncodedRegex( '{cke_protected' ) +
				')(_[0-9]*)?' +
				createEncodedRegex( '}' ) +
				')' , 'gi' );
		}

		function createEncodedRegex( str ) {
			return CKEDITOR.tools.array.reduce( str.split( '' ), function( cur, character ) {
				// Produce case insensitive regex. `i` flag is not enough thus code entities differs
				// depending on case sensitivity.
				var lowerCase = character.toLowerCase(),
					upperCase = character.toUpperCase(),
					regex = createCharacterEncodedRegex( lowerCase );

				if ( lowerCase !== upperCase ) {
					regex += '|' + createCharacterEncodedRegex( upperCase );
				}

				cur += '(' + regex + ')';

				return cur;
			}, '' );
		}

		function createCharacterEncodedRegex( character ) {
			var map = getCharRegexMap( character ),
				charRegex = character;

			for ( var code in map ) {
				if ( map[ code ] ) {
					charRegex += '|' + map[ code ];
				}
			}

			return charRegex;
		}

		function getCharRegexMap( character ) {
			var entities = {
				'<': '&lt;',
				'>': '&gt;',
				':': '&colon;'
			},
				charCode = character.charCodeAt( 0 ),
				hex = charCode.toString( 16 );

			return {
				// `;` is optional and HTML parser is able to recognize codes without it.
				htmlCode: '&#' + charCode + ';?',
				// Hexadecimal value is valid despite leading zero padding e.g. `&#x0065` === `&#x65`.
				hex: '&#x0*' + hex + ';?',
				entity: entities[ character ]
			};
		}
	} )();

	function generateRandomNumber() {
		var cryptoApi = window.crypto || window.msCrypto;

		if ( cryptoApi ) {
			return cryptoApi.getRandomValues( new Uint32Array( 1 ) )[ 0 ];
		}

		return Math.floor( Math.random() *  9000000000 + 1000000000 );
	}
} )();

/**
 * Whether a filler text (non-breaking space entity &mdash; `&nbsp;`) will be
 * inserted into empty block elements in HTML output.
 * This is used to render block elements properly with `line-height`.
 * When a function is specified instead, it will be passed a {@link CKEDITOR.htmlParser.element}
 * to decide whether adding the filler text by expecting a Boolean return value.
 *
 *		config.fillEmptyBlocks = false; // Prevent filler nodes in all empty blocks.
 *
 *		// Prevent filler node only in float cleaners.
 *		config.fillEmptyBlocks = function( element ) {
 *			if ( element.attributes[ 'class' ].indexOf( 'clear-both' ) != -1 )
 *				return false;
 *		};
 *
 * @since 3.5.0
 * @cfg {Boolean/Function} [fillEmptyBlocks=true]
 * @member CKEDITOR.config
 */

/**
 * This event is fired by the {@link CKEDITOR.htmlDataProcessor} when input HTML
 * is to be purified by the {@link CKEDITOR.htmlDataProcessor#toHtml} method.
 *
 * By adding listeners with different priorities it is possible
 * to process input HTML on different stages:
 *
 *	* 1-4: Data is available in the original string format.
 *	* 5: Data is initially filtered with regexp patterns and parsed to
 *		{@link CKEDITOR.htmlParser.fragment} {@link CKEDITOR.htmlParser.element}.
 *	* 5-9: Data is available in the parsed format, but {@link CKEDITOR.htmlDataProcessor#dataFilter}
 *		is not applied yet.
 *	* 6: Data is filtered with the {@link CKEDITOR.filter content filter}.
 *	* 10: Data is processed with {@link CKEDITOR.htmlDataProcessor#dataFilter}.
 *	* 10-14: Data is available in the parsed format and {@link CKEDITOR.htmlDataProcessor#dataFilter}
 *		has already been applied.
 *	* 15: Data is written back to an HTML string.
 *	* 15-*: Data is available in an HTML string.
 *
 * For example to be able to process parsed, but not yet filtered data add listener this way:
 *
 *		editor.on( 'toHtml', function( evt) {
 *			evt.data.dataValue; // -> CKEDITOR.htmlParser.fragment instance
 *		}, null, null, 7 );
 *
 * @since 4.1.0
 * @event toHtml
 * @member CKEDITOR.editor
 * @param {CKEDITOR.editor} editor This editor instance.
 * @param data
 * @param {String/CKEDITOR.htmlParser.fragment/CKEDITOR.htmlParser.element} data.dataValue Input data to be purified.
 * @param {String} data.context See {@link CKEDITOR.htmlDataProcessor#toHtml} The `context` argument.
 * @param {Boolean} data.fixForBody See {@link CKEDITOR.htmlDataProcessor#toHtml} The `fixForBody` argument.
 * @param {Boolean} data.dontFilter See {@link CKEDITOR.htmlDataProcessor#toHtml} The `dontFilter` argument.
 * @param {Boolean} data.filter See {@link CKEDITOR.htmlDataProcessor#toHtml} The `filter` argument.
 * @param {Boolean} data.enterMode See {@link CKEDITOR.htmlDataProcessor#toHtml} The `enterMode` argument.
 * @param {Boolean} [data.protectedWhitespaces] See {@link CKEDITOR.htmlDataProcessor#toHtml} The `protectedWhitespaces` argument.
 */

/**
 * This event is fired when {@link CKEDITOR.htmlDataProcessor} is converting
 * internal HTML to output data HTML.
 *
 * By adding listeners with different priorities it is possible
 * to process input HTML on different stages:
 *
 *	* 1-4: Data is available in the original string format.
 *	* 5: Data is initially filtered with regexp patterns and parsed to
 *		{@link CKEDITOR.htmlParser.fragment} {@link CKEDITOR.htmlParser.element}.
 *	* 5-9: Data is available in the parsed format, but {@link CKEDITOR.htmlDataProcessor#htmlFilter}
 *		is not applied yet.
 *	* 10: Data is filtered with {@link CKEDITOR.htmlDataProcessor#htmlFilter}.
 *  * 11: Data is filtered with the {CKEDITOR.filter content filter} (on output the content filter makes
 *		only transformations, without filtering).
 *	* 10-14: Data is available in the parsed format and {@link CKEDITOR.htmlDataProcessor#htmlFilter}
 *		has already been applied.
 *	* 15: Data is written back to an HTML string.
 *	* 15-*: Data is available in an HTML string.
 *
 * For example to be able to process parsed and already processed data add listener this way:
 *
 *		editor.on( 'toDataFormat', function( evt) {
 *			evt.data.dataValue; // -> CKEDITOR.htmlParser.fragment instance
 *		}, null, null, 12 );
 *
 * @since 4.1.0
 * @event toDataFormat
 * @member CKEDITOR.editor
 * @param {CKEDITOR.editor} editor This editor instance.
 * @param data
 * @param {String/CKEDITOR.htmlParser.fragment/CKEDITOR.htmlParser.element} data.dataValue Output data to be prepared.
 * @param {String} data.context See {@link CKEDITOR.htmlDataProcessor#toDataFormat} The `context` argument.
 * @param {Boolean} data.filter See {@link CKEDITOR.htmlDataProcessor#toDataFormat} The `filter` argument.
 * @param {Boolean} data.enterMode See {@link CKEDITOR.htmlDataProcessor#toDataFormat} The `enterMode` argument.
 */