CSS: simplify hack of css getter for the computed values

Ref gh-1906

src/css/curCSS.js

@@ -72,7 +72,7 @@ if ( window.getComputedStyle ) {
 	};
 
 	curCSS = function( elem, name, computed ) {
-		var left, rs, rsLeft, ret,
+		var left, ret,
 			style = elem.style;
 
 		computed = computed || getStyles( elem );
@@ -84,7 +84,7 @@ if ( window.getComputedStyle ) {
 			ret = style[ name ];
 		}
 
-		// From the awesome hack by Dean Edwards
+		// Simplified hack by Dean Edwards
 		// http://erik.eae.net/archives/2007/07/27/18.54.15/#comment-102291
 
 		// If we're not dealing with a regular pixel number
@@ -97,21 +97,13 @@ if ( window.getComputedStyle ) {
 
 			// Remember the original values
 			left = style.left;
-			rs = elem.runtimeStyle;
-			rsLeft = rs && rs.left;
 
 			// Put in the new values to get a computed value out
-			if ( rsLeft ) {
-				rs.left = elem.currentStyle.left;
-			}
 			style.left = name === "fontSize" ? "1em" : ret;
 			ret = style.pixelLeft + "px";
 
 			// Revert the changed values
 			style.left = left;
-			if ( rsLeft ) {
-				rs.left = rsLeft;
-			}
 		}
 
 		// Support: IE<9

test/data/testsuite.css

@@ -163,3 +163,8 @@ section { background:#f0f; display:block; }
 	-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";
 }
 
+.get-computed-value {
+	padding-left: 50%;
+	width: 20%;
+	font-size: 2em;
+}

test/unit/css.js

@@ -119,6 +119,17 @@ test("css(String|Hash)", function() {
 		"Make sure that a string z-index is returned from css('z-index') (#14432)." );
 });
 
+test( "css(String) computed values", 3, function() {
+	var div = jQuery( "<div/>" ).addClass( "get-computed-value" ),
+		fixture = document.getElementById( "qunit-fixture" );
+
+	div.appendTo( fixture );
+	strictEqual( div.css( "padding-left" ), "500px", "should get computed value for padding-left property" );
+	strictEqual( div.css( "width" ), "200px", "should get computed value for width property" );
+	strictEqual( div.css( "font-size" ), "32px", "should get computed value for font-size property" );
+});
+
+
 test( "css() explicit and relative values", 29, function() {
 	var $elem = jQuery("#nothiddendiv");