Merge pull request jquery#416 from gnarf37/ticket_6652

CSS: Remove filter from style when setting opacity to 1 - Fixes #6652 - R

src/css.js

@@ -211,18 +211,29 @@ if ( !jQuery.support.opacity ) {
 
 		set: function( elem, value ) {
 			var style = elem.style,
-				currentStyle = elem.currentStyle;
+				currentStyle = elem.currentStyle,
+				opacity = jQuery.isNaN( value ) ? "" : "alpha(opacity=" + value * 100 + ")",
+				filter = currentStyle && currentStyle.filter || style.filter || "";
 
 			// IE has trouble with opacity if it does not have layout
 			// Force it by setting the zoom level
 			style.zoom = 1;
 
-			// Set the alpha filter to set the opacity
-			var opacity = jQuery.isNaN( value ) ?
-				"" :
-				"alpha(opacity=" + value * 100 + ")",
-				filter = currentStyle && currentStyle.filter || style.filter || "";
+			// if setting opacity to 1, and no other filters exist - attempt to remove filter attribute #6652
+			if ( value >= 1 && jQuery.trim( filter.replace( ralpha, "" ) ) === "" ) {
+
+				// Setting style.filter to null, "" & " " still leave "filter:" in the cssText
+				// if "filter:" is present at all, clearType is disabled, we want to avoid this
+				// style.removeAttribute is IE Only, but so apparently is this code path...
+				style.removeAttribute( "filter" );
+
+				// if there there is no filter style applied in a css rule, we are done
+				if ( currentStyle && !currentStyle.filter ) {
+					return;
+				}
+			}
 
+			// otherwise, set new filter values
 			style.filter = ralpha.test( filter ) ?
 				filter.replace( ralpha, opacity ) :
 				filter + " " + opacity;

test/data/testsuite.css

@@ -121,3 +121,5 @@ dfn { display: none; }
 /* #9239 Attach a background to the body( avoid crashes in removing the test element in support ) */
 body, div { background: url(http://static.jquery.com/files/rocker/images/logo_jquery_215x53.gif) no-repeat -1000px 0; }
 
+/* #6652 REMOVE FILTER:ALPHA(OPACITY=100) AFTER ANIMATION */
+#t6652 div { filter: alpha(opacity=50); }

test/index.html

@@ -226,6 +226,9 @@ <h2 id="qunit-userAgent"></h2>
 			<div id="t2037">
 				<div><div class="hidden">hidden</div></div>
 			</div>
+			<div id="t6652">
+				<div></div>
+			</div>
 		</div>
 
 		<div id="tabindex-tests">

test/unit/css.js

@@ -259,6 +259,23 @@ if ( !jQuery.support.opacity ) {
 		jQuery("#foo").css("filter", filterVal3).css("opacity", 1);
 		ok( jQuery("#foo").css("filter").indexOf(filterVal3) !== -1, "Setting opacity in IE doesn't clobber other filters" );
 	});
+
+	test( "Setting opacity to 1 properly removes filter: style (#6652)", function() {
+		var rfilter = /filter:[^;]*/i,
+			test = jQuery( "#t6652" ).css( "opacity", 1 ),
+			test2 = test.find( "div" ).css( "opacity", 1 );
+
+		function hasFilter( elem ) {
+			var match = rfilter.exec( elem[0].style.cssText );
+			if ( match ) {
+				return true;
+			}
+			return false;
+		}
+		expect( 2 );
+		ok( !hasFilter( test ), "Removed filter attribute on element without filter in stylesheet" );
+		ok( hasFilter( test2 ), "Filter attribute remains on element that had filter in stylesheet" );
+	});
 }
 
 test("css(String, Function)", function() {