Core: Drop support for IE (all versions)

Author: mgol

.github/workflows/browserstack.yml

@@ -21,7 +21,6 @@ jobs:
       fail-fast: false
       matrix:
         BROWSER:
-          - 'IE_11'
           - 'Safari_latest'
           - 'Safari_latest-1'
           - 'Chrome_latest'

src/ajax.js

@@ -455,20 +455,12 @@ jQuery.extend( {
 						if ( !responseHeaders ) {
 							responseHeaders = {};
 							while ( ( match = rheaders.exec( responseHeadersString ) ) ) {
-
-								// Support: IE 11+
-								// `getResponseHeader( key )` in IE doesn't combine all header
-								// values for the provided key into a single result with values
-								// joined by commas as other browsers do. Instead, it returns
-								// them on separate lines.
-								responseHeaders[ match[ 1 ].toLowerCase() + " " ] =
-									( responseHeaders[ match[ 1 ].toLowerCase() + " " ] || [] )
-										.concat( match[ 2 ] );
+								responseHeaders[ match[ 1 ].toLowerCase() + " " ] = match[ 2 ];
 							}
 						}
 						match = responseHeaders[ key.toLowerCase() + " " ];
 					}
-					return match == null ? null : match.join( ", " );
+					return match == null ? null : match;
 				},
 
 				// Raw string
@@ -542,24 +534,8 @@ jQuery.extend( {
 		// A cross-domain request is in order when the origin doesn't match the current origin.
 		if ( s.crossDomain == null ) {
 			urlAnchor = document.createElement( "a" );
-
-			// Support: IE <=8 - 11+
-			// IE throws exception on accessing the href property if url is malformed,
-			// e.g. http://example.com:80x/
-			try {
-				urlAnchor.href = s.url;
-
-				// Support: IE <=8 - 11+
-				// Anchor's host property isn't correctly set when s.url is relative
-				urlAnchor.href = urlAnchor.href;
-				s.crossDomain = originAnchor.protocol + "//" + originAnchor.host !==
-					urlAnchor.protocol + "//" + urlAnchor.host;
-			} catch ( e ) {
-
-				// If there is an error parsing the URL, assume it is crossDomain,
-				// it can be rejected by the transport if it is invalid
-				s.crossDomain = true;
-			}
+			urlAnchor.href = s.url;
+			s.crossDomain = originAnchor.origin !== urlAnchor.origin;
 		}
 
 		// Apply prefilters

src/ajax/load.js

@@ -50,8 +50,8 @@ jQuery.fn.load = function( url, params, callback ) {
 
 			self.html( selector ?
 
-				// If a selector was specified, locate the right elements in a dummy div
-				// Exclude scripts to avoid IE 'Permission Denied' errors
+				// If a selector was specified, locate the right elements in a dummy div.
+				// Exclude scripts.
 				jQuery( "<div>" ).append( jQuery.parseHTML( responseText ) ).find( selector ) :
 
 				// Otherwise use the full result

src/attributes/attr.js

@@ -1,8 +1,6 @@
 import { jQuery } from "../core.js";
 import { access } from "../core/access.js";
-import { nodeName } from "../core/nodeName.js";
 import { rnothtmlwhite } from "../var/rnothtmlwhite.js";
-import { isIE } from "../var/isIE.js";
 
 jQuery.fn.extend( {
 	attr: function( name, value ) {
@@ -86,20 +84,3 @@ jQuery.extend( {
 		}
 	}
 } );
-
-// Support: IE <=11+
-// An input loses its value after becoming a radio
-if ( isIE ) {
-	jQuery.attrHooks.type = {
-		set: function( elem, value ) {
-			if ( value === "radio" && nodeName( elem, "input" ) ) {
-				var val = elem.value;
-				elem.setAttribute( "type", value );
-				if ( val ) {
-					elem.value = val;
-				}
-				return value;
-			}
-		}
-	};
-}

src/attributes/prop.js

@@ -1,6 +1,5 @@
 import { jQuery } from "../core.js";
 import { access } from "../core/access.js";
-import { isIE } from "../var/isIE.js";
 
 var rfocusable = /^(?:input|select|textarea|button)$/i,
 	rclickable = /^(?:a|area)$/i;
@@ -54,7 +53,6 @@ jQuery.extend( {
 		tabIndex: {
 			get: function( elem ) {
 
-				// Support: IE <=9 - 11+
 				// elem.tabIndex doesn't always return the
 				// correct value when it hasn't been explicitly set
 				// Use proper attribute retrieval (trac-12072)
@@ -85,39 +83,6 @@ jQuery.extend( {
 	}
 } );
 
-// Support: IE <=11+
-// Accessing the selectedIndex property forces the browser to respect
-// setting selected on the option. The getter ensures a default option
-// is selected when in an optgroup. ESLint rule "no-unused-expressions"
-// is disabled for this code since it considers such accessions noop.
-if ( isIE ) {
-	jQuery.propHooks.selected = {
-		get: function( elem ) {
-
-			var parent = elem.parentNode;
-			if ( parent && parent.parentNode ) {
-				// eslint-disable-next-line no-unused-expressions
-				parent.parentNode.selectedIndex;
-			}
-			return null;
-		},
-		set: function( elem ) {
-
-
-			var parent = elem.parentNode;
-			if ( parent ) {
-				// eslint-disable-next-line no-unused-expressions
-				parent.selectedIndex;
-
-				if ( parent.parentNode ) {
-					// eslint-disable-next-line no-unused-expressions
-					parent.parentNode.selectedIndex;
-				}
-			}
-		}
-	};
-}
-
 jQuery.each( [
 	"tabIndex",
 	"readOnly",

src/attributes/val.js

@@ -1,6 +1,4 @@
 import { jQuery } from "../core.js";
-import { isIE } from "../var/isIE.js";
-import { stripAndCollapse } from "../core/stripAndCollapse.js";
 import { nodeName } from "../core/nodeName.js";
 
 import "../core/init.js";
@@ -140,23 +138,6 @@ jQuery.extend( {
 	}
 } );
 
-if ( isIE ) {
-	jQuery.valHooks.option = {
-		get: function( elem ) {
-
-			var val = elem.getAttribute( "value" );
-			return val != null ?
-				val :
-
-				// Support: IE <=10 - 11+
-				// option.text throws exceptions (trac-14686, trac-14858)
-				// Strip and collapse whitespace
-				// https://html.spec.whatwg.org/#strip-and-collapse-whitespace
-				stripAndCollapse( jQuery.text( elem ) );
-		}
-	};
-}
-
 // Radios and checkboxes getter/setter
 jQuery.each( [ "radio", "checkbox" ], function() {
 	jQuery.valHooks[ this ] = {

src/core.js

@@ -323,14 +323,7 @@ jQuery.extend( {
 	contains: function( a, b ) {
 		var bup = b && b.parentNode;
 
-		return a === bup || !!( bup && bup.nodeType === 1 && (
-
-			// Support: IE 9 - 11+
-			// IE doesn't have `contains` on SVG.
-			a.contains ?
-				a.contains( bup ) :
-				a.compareDocumentPosition && a.compareDocumentPosition( bup ) & 16
-		) );
+		return a === bup || !!( bup && bup.nodeType === 1 && a.contains( bup ) );
 	},
 
 	merge: function( first, second ) {
@@ -395,7 +388,7 @@ jQuery.extend( {
 		}
 
 		// Flatten any nested arrays
-		return flat( ret );
+		return flat.call( ret );
 	},
 
 	// A global GUID counter for objects

src/core/isAttached.js

@@ -1,19 +1,8 @@
 import { jQuery } from "../core.js";
-import { documentElement } from "../var/documentElement.js";
 
-var isAttached = function( elem ) {
-		return jQuery.contains( elem.ownerDocument, elem ) ||
-			elem.getRootNode( composed ) === elem.ownerDocument;
-	},
-	composed = { composed: true };
+var composed = { composed: true };
 
-// Support: IE 9 - 11+
-// Check attachment across shadow DOM boundaries when possible (gh-3504).
-// Provide a fallback for browsers without Shadow DOM v1 support.
-if ( !documentElement.getRootNode ) {
-	isAttached = function( elem ) {
-		return jQuery.contains( elem.ownerDocument, elem );
-	};
+export function isAttached( elem ) {
+	return jQuery.contains( elem.ownerDocument, elem ) ||
+		elem.getRootNode( composed ) === elem.ownerDocument;
 }
-
-export { isAttached };

src/core/parseXML.js

@@ -7,21 +7,15 @@ jQuery.parseXML = function( data ) {
 		return null;
 	}
 
-	// Support: IE 9 - 11+
-	// IE throws on parseFromString with invalid input.
-	try {
-		xml = ( new window.DOMParser() ).parseFromString( data, "text/xml" );
-	} catch ( e ) {}
+	xml = ( new window.DOMParser() ).parseFromString( data, "text/xml" );
 
-	parserErrorElem = xml && xml.getElementsByTagName( "parsererror" )[ 0 ];
-	if ( !xml || parserErrorElem ) {
-		jQuery.error( "Invalid XML: " + (
-			parserErrorElem ?
-				jQuery.map( parserErrorElem.childNodes, function( el ) {
-					return el.textContent;
-				} ).join( "\n" ) :
-				data
-		) );
+	parserErrorElem = xml.getElementsByTagName( "parsererror" )[ 0 ];
+	if ( parserErrorElem ) {
+		jQuery.error( "Invalid XML: " +
+			jQuery.map( parserErrorElem.childNodes, function( el ) {
+				return el.textContent;
+			} ).join( "\n" )
+		);
 	}
 	return xml;
 };

src/css.js

@@ -1,13 +1,12 @@
 import { jQuery } from "./core.js";
 import { access } from "./core/access.js";
+import { camelCase } from "./core/camelCase.js";
 import { nodeName } from "./core/nodeName.js";
 import { rcssNum } from "./var/rcssNum.js";
-import { isIE } from "./var/isIE.js";
 import { rnumnonpx } from "./css/var/rnumnonpx.js";
 import { rcustomProp } from "./css/var/rcustomProp.js";
 import { cssExpand } from "./css/var/cssExpand.js";
 import { isAutoPx } from "./css/isAutoPx.js";
-import { cssCamelCase } from "./css/cssCamelCase.js";
 import { getStyles } from "./css/var/getStyles.js";
 import { swap } from "./css/var/swap.js";
 import { curCSS } from "./css/curCSS.js";
@@ -120,8 +119,7 @@ function getWidthOrHeight( elem, dimension, extra ) {
 
 		// To avoid forcing a reflow, only fetch boxSizing if we need it (gh-4322).
 		// Fake content-box until we know it's needed to know the true value.
-		boxSizingNeeded = isIE || extra,
-		isBorderBox = boxSizingNeeded &&
+		isBorderBox = extra &&
 			jQuery.css( elem, "boxSizing", false, styles ) === "border-box",
 		valueIsBorderBox = isBorderBox,
 
@@ -143,14 +141,6 @@ function getWidthOrHeight( elem, dimension, extra ) {
 		// This happens for inline elements with no explicit setting (gh-3571)
 		val === "auto" ||
 
-		// Support: IE 9 - 11+
-		// Use offsetWidth/offsetHeight for when box sizing is unreliable.
-		// In those cases, the computed value can be trusted to be border-box.
-		( isIE && isBorderBox ) ||
-
-		// Support: IE 10 - 11+
-		// IE misreports `getComputedStyle` of table rows with width/height
-		// set in CSS while `offset*` properties report correct values.
 		// Support: Firefox 70+
 		// Firefox includes border widths
 		// in computed dimensions for table rows. (gh-4529)
@@ -204,7 +194,7 @@ jQuery.extend( {
 
 		// Make sure that we're working with the right name
 		var ret, type, hooks,
-			origName = cssCamelCase( name ),
+			origName = camelCase( name ),
 			isCustomProp = rcustomProp.test( name ),
 			style = elem.style;
 
@@ -240,12 +230,6 @@ jQuery.extend( {
 				value += ret && ret[ 3 ] || ( isAutoPx( origName ) ? "px" : "" );
 			}
 
-			// Support: IE <=9 - 11+
-			// background-* props of a cloned element affect the source element (trac-8908)
-			if ( isIE && value === "" && name.indexOf( "background" ) === 0 ) {
-				style[ name ] = "inherit";
-			}
-
 			// If a hook was provided, use that value, otherwise just set the specified value
 			if ( !hooks || !( "set" in hooks ) ||
 				( value = hooks.set( elem, value, extra ) ) !== undefined ) {
@@ -273,7 +257,7 @@ jQuery.extend( {
 
 	css: function( elem, name, extra, styles ) {
 		var val, num, hooks,
-			origName = cssCamelCase( name ),
+			origName = camelCase( name ),
 			isCustomProp = rcustomProp.test( name );
 
 		// Make sure that we're working with the right name. We don't
@@ -316,17 +300,14 @@ jQuery.each( [ "height", "width" ], function( _i, dimension ) {
 		get: function( elem, computed, extra ) {
 			if ( computed ) {
 
-				// Certain elements can have dimension info if we invisibly show them
+				// Certain elements can have dimension info if we invisibly show them,
 				// but it must have a current display style that would benefit
 				return rdisplayswap.test( jQuery.css( elem, "display" ) ) &&
 
 					// Support: Safari <=8 - 12+, Chrome <=73+
 					// Table columns in WebKit/Blink have non-zero offsetWidth & zero
 					// getBoundingClientRect().width unless display is changed.
-					// Support: IE <=11+
-					// Running getBoundingClientRect on a disconnected node
-					// in IE throws an error.
-					( !elem.getClientRects().length || !elem.getBoundingClientRect().width ) ?
+					!elem.getBoundingClientRect().width ?
 					swap( elem, cssShow, function() {
 						return getWidthOrHeight( elem, dimension, extra );
 					} ) :