Fix #10754. Have jQuery.swap() return the value of its callback.

src/css.js

@@ -140,20 +140,23 @@ jQuery.extend({
 
 	// A method for quickly swapping in/out CSS properties to get correct calculations
 	swap: function( elem, options, callback ) {
-		var old = {};
+		var old = {},
+			ret, name;
 
 		// Remember the old values, and insert the new ones
-		for ( var name in options ) {
+		for ( name in options ) {
 			old[ name ] = elem.style[ name ];
 			elem.style[ name ] = options[ name ];
 		}
 
-		callback.call( elem );
+		ret = callback.call( elem );
 
 		// Revert the old values
 		for ( name in options ) {
 			elem.style[ name ] = old[ name ];
 		}
+
+		return ret;
 	}
 });
 
@@ -163,18 +166,14 @@ jQuery.curCSS = jQuery.css;
 jQuery.each(["height", "width"], function( i, name ) {
 	jQuery.cssHooks[ name ] = {
 		get: function( elem, computed, extra ) {
-			var val;
-
 			if ( computed ) {
 				if ( elem.offsetWidth !== 0 ) {
 					return getWH( elem, name, extra );
 				} else {
-					jQuery.swap( elem, cssShow, function() {
-						val = getWH( elem, name, extra );
+					return jQuery.swap( elem, cssShow, function() {
+						return getWH( elem, name, extra );
 					});
 				}
-
-				return val;
 			}
 		},
 
@@ -243,15 +242,13 @@ jQuery(function() {
 			get: function( elem, computed ) {
 				// WebKit Bug 13343 - getComputedStyle returns wrong value for margin-right
 				// Work around by temporarily setting element display to inline-block
-				var ret;
-				jQuery.swap( elem, { "display": "inline-block" }, function() {
+				return jQuery.swap( elem, { "display": "inline-block" }, function() {
 					if ( computed ) {
-						ret = curCSS( elem, "margin-right", "marginRight" );
+						return curCSS( elem, "margin-right", "marginRight" );
 					} else {
-						ret = elem.style.marginRight;
+						return elem.style.marginRight;
 					}
 				});
-				return ret;
 			}
 		};
 	}