support.js

jQuery.support = (function() {

	var support,
		all,
		a,
		select,
		opt,
		input,
		fragment,
		eventName,
		i,
		isSupported,
		clickFn,
		div = document.createElement("div");

	// Preliminary tests
	div.setAttribute( "className", "t" );
	div.innerHTML = "  <link/><table></table><a href='/a'>a</a><input type='checkbox'/>";

	all = div.getElementsByTagName("*");
	a = div.getElementsByTagName("a")[ 0 ];
	a.style.cssText = "top:1px;float:left;opacity:.5";

	// Can't get basic test support
	if ( !all || !all.length || !a ) {
		return {};
	}

	// First batch of supports tests
	select = document.createElement("select");
	opt = select.appendChild( document.createElement("option") );
	input = div.getElementsByTagName("input")[ 0 ];

	support = {
		// IE strips leading whitespace when .innerHTML is used
		leadingWhitespace: ( div.firstChild.nodeType === 3 ),

		// Make sure that tbody elements aren't automatically inserted
		// IE will insert them into empty tables
		tbody: !div.getElementsByTagName("tbody").length,

		// Make sure that link elements get serialized correctly by innerHTML
		// This requires a wrapper element in IE
		htmlSerialize: !!div.getElementsByTagName("link").length,

		// Get the style information from getAttribute
		// (IE uses .cssText instead)
		style: /top/.test( a.getAttribute("style") ),

		// Make sure that URLs aren't manipulated
		// (IE normalizes it by default)
		hrefNormalized: ( a.getAttribute("href") === "/a" ),

		// Make sure that element opacity exists
		// (IE uses filter instead)
		// Use a regex to work around a WebKit issue. See #5145
		opacity: /^0.5/.test( a.style.opacity ),

		// Verify style float existence
		// (IE uses styleFloat instead of cssFloat)
		cssFloat: !!a.style.cssFloat,

		// Make sure that if no value is specified for a checkbox
		// that it defaults to "on".
		// (WebKit defaults to "" instead)
		checkOn: ( input.value === "on" ),

		// Make sure that a selected-by-default option has a working selected property.
		// (WebKit defaults to false instead of true, IE too, if it's in an optgroup)
		optSelected: opt.selected,

		// Test setAttribute on camelCase class. If it works, we need attrFixes when doing get/setAttribute (ie6/7)
		getSetAttribute: div.className !== "t",

		// Tests for enctype support on a form(#6743)
		enctype: !!document.createElement("form").enctype,

		// Makes sure cloning an html5 element does not cause problems
		// Where outerHTML is undefined, this still works
		html5Clone: document.createElement("nav").cloneNode( true ).outerHTML !== "<:nav></:nav>",

		// jQuery.support.boxModel DEPRECATED in 1.8 since we don't support Quirks Mode
		boxModel: ( document.compatMode === "CSS1Compat" ),

		// Will be defined later
		submitBubbles: true,
		changeBubbles: true,
		focusinBubbles: false,
		deleteExpando: true,
		noCloneEvent: true,
		inlineBlockNeedsLayout: false,
		shrinkWrapBlocks: false,
		reliableMarginRight: true,
		boxSizingReliable: true,
		pixelPosition: false
	};

	// Make sure checked status is properly cloned
	input.checked = true;
	support.noCloneChecked = input.cloneNode( true ).checked;

	// Make sure that the options inside disabled selects aren't marked as disabled
	// (WebKit marks them as disabled)
	select.disabled = true;
	support.optDisabled = !opt.disabled;

	// Test to see if it's possible to delete an expando from an element
	// Fails in Internet Explorer
	try {
		delete div.test;
	} catch( e ) {
		support.deleteExpando = false;
	}

	if ( !div.addEventListener && div.attachEvent && div.fireEvent ) {
		div.attachEvent( "onclick", clickFn = function() {
			// Cloning a node shouldn't copy over any
			// bound event handlers (IE does this)
			support.noCloneEvent = false;
		});
		div.cloneNode( true ).fireEvent("onclick");
		div.detachEvent( "onclick", clickFn );
	}

	// Check if a radio maintains its value
	// after being appended to the DOM
	input = document.createElement("input");
	input.value = "t";
	input.setAttribute( "type", "radio" );
	support.radioValue = input.value === "t";

	input.setAttribute( "checked", "checked" );

	// #11217 - WebKit loses check when the name is after the checked attribute
	input.setAttribute( "name", "t" );

	div.appendChild( input );
	fragment = document.createDocumentFragment();
	fragment.appendChild( div.lastChild );

	// WebKit doesn't clone checked state correctly in fragments
	support.checkClone = fragment.cloneNode( true ).cloneNode( true ).lastChild.checked;

	// Check if a disconnected checkbox will retain its checked
	// value of true after appended to the DOM (IE6/7)
	support.appendChecked = input.checked;

	fragment.removeChild( input );
	fragment.appendChild( div );

	// Technique from Juriy Zaytsev
	// http://perfectionkills.com/detecting-event-support-without-browser-sniffing/
	// We only care about the case where non-standard event systems
	// are used, namely in IE. Short-circuiting here helps us to
	// avoid an eval call (in setAttribute) which can cause CSP
	// to go haywire. See: https://developer.mozilla.org/en/Security/CSP
	if ( div.attachEvent ) {
		for ( i in {
			submit: true,
			change: true,
			focusin: true
		}) {
			eventName = "on" + i;
			isSupported = ( eventName in div );
			if ( !isSupported ) {
				div.setAttribute( eventName, "return;" );
				isSupported = ( typeof div[ eventName ] === "function" );
			}
			support[ i + "Bubbles" ] = isSupported;
		}
	}

	// Run tests that need a body at doc ready
	jQuery(function() {
		var container, div, tds, marginDiv,
			divReset = "padding:0;margin:0;border:0;display:block;overflow:hidden;",
			body = document.getElementsByTagName("body")[0];

		if ( !body ) {
			// Return for frameset docs that don't have a body
			return;
		}

		container = document.createElement("div");
		container.style.cssText = "visibility:hidden;border:0;width:0;height:0;position:static;top:0;margin-top:1px";
		body.insertBefore( container, body.firstChild );

		// Construct the test element
		div = document.createElement("div");
		container.appendChild( div );

		// Check if table cells still have offsetWidth/Height when they are set
		// to display:none and there are still other visible table cells in a
		// table row; if so, offsetWidth/Height are not reliable for use when
		// determining if an element has been hidden directly using
		// display:none (it is still safe to use offsets if a parent element is
		// hidden; don safety goggles and see bug #4512 for more information).
		// (only IE 8 fails this test)
		div.innerHTML = "<table><tr><td></td><td>t</td></tr></table>";
		tds = div.getElementsByTagName("td");
		tds[ 0 ].style.cssText = "padding:0;margin:0;border:0;display:none";
		isSupported = ( tds[ 0 ].offsetHeight === 0 );

		tds[ 0 ].style.display = "";
		tds[ 1 ].style.display = "none";

		// Check if empty table cells still have offsetWidth/Height
		// (IE <= 8 fail this test)
		support.reliableHiddenOffsets = isSupported && ( tds[ 0 ].offsetHeight === 0 );

		// Check box-sizing and margin behavior
		div.innerHTML = "";
		div.style.cssText = "box-sizing:border-box;-moz-box-sizing:border-box;-webkit-box-sizing:border-box;padding:1px;border:1px;display:block;width:4px;margin-top:1%;position:absolute;top:1%;";
		support.boxSizing = ( div.offsetWidth === 4 );
		support.doesNotIncludeMarginInBodyOffset = ( body.offsetTop !== 1 );

		// NOTE: To any future maintainer, window.getComputedStyle was used here
		// instead of getComputedStyle because it gave a better gzip size.
		// The difference between window.getComputedStyle and getComputedStyle is
		// 7 bytes
		if ( window.getComputedStyle ) {
			support.pixelPosition = ( window.getComputedStyle( div, null ) || {} ).top !== "1%";
			support.boxSizingReliable = ( window.getComputedStyle( div, null ) || { width: "4px" } ).width === "4px";

			// Check if div with explicit width and no margin-right incorrectly
			// gets computed margin-right based on width of container. For more
			// info see bug #3333
			// Fails in WebKit before Feb 2011 nightlies
			// WebKit Bug 13343 - getComputedStyle returns wrong value for margin-right
			marginDiv = document.createElement("div");
			marginDiv.style.cssText = div.style.cssText = divReset;
			marginDiv.style.marginRight = marginDiv.style.width = "0";
			div.style.width = "1px";
			div.appendChild( marginDiv );
			support.reliableMarginRight =
				!parseFloat( ( window.getComputedStyle( marginDiv, null ) || {} ).marginRight );
		}

		if ( typeof div.style.zoom !== "undefined" ) {
			// Check if natively block-level elements act like inline-block
			// elements when setting their display to 'inline' and giving
			// them layout
			// (IE < 8 does this)
			div.innerHTML = "";
			div.style.cssText = divReset + "width:1px;padding:1px;display:inline;zoom:1";
			support.inlineBlockNeedsLayout = ( div.offsetWidth === 3 );

			// Check if elements with layout shrink-wrap their children
			// (IE 6 does this)
			div.style.display = "block";
			div.style.overflow = "visible";
			div.innerHTML = "<div></div>";
			div.firstChild.style.width = "5px";
			support.shrinkWrapBlocks = ( div.offsetWidth !== 3 );

			container.style.zoom = 1;
		}

		// Null elements to avoid leaks in IE
		body.removeChild( container );
		container = div = tds = marginDiv = null;
	});

	// Null elements to avoid leaks in IE
	fragment.removeChild( div );
	all = a = select = opt = input = fragment = div = null;

	return support;
})();