Add support check, added assertion to check if cleared, add edge case for backgroundPosition

src/css.js

@@ -204,6 +204,9 @@ jQuery.extend({
 
 			// 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 ) {
+				// IE9/10 Clearing Cloned Style Clear's Original Style. Fixes bug #8908
+				value = !jQuery.support.clearCloneStyle && value === "" && name.match( /backgroundPosition/ ) ? "0% 0%" : value;
+
 				// Wrapped to prevent IE from throwing errors when 'invalid' values are provided
 				// Fixes bug #5509
 				try {

src/manipulation.js

@@ -585,14 +585,13 @@ jQuery.extend({
 		var srcElements,
 			destElements,
 			i,
-			clone,
-			fix8908;
+			clone;
 
 		if ( jQuery.support.html5Clone || jQuery.isXMLDoc(elem) || !rnoshimcache.test( "<" + elem.nodeName + ">" ) ) {
 			// Fixes #8909 - By accessing one of the element's computed styles it breaks the
 			// connection with the cloned element's styles in IE9/10
-			if ( elem.nodeType === 1 && window.getComputedStyle ) {
-				fix8908 = ( window.getComputedStyle( elem, null ) || {} ).backgroundImage;
+			if ( !jQuery.support.clearCloneStyle && elem.nodeType === 1 && window.getComputedStyle ) {
+				i = ( window.getComputedStyle( elem, null ) || {} ).backgroundPosition;
 			}
 
 			clone = elem.cloneNode( true );

src/support.js

@@ -170,6 +170,19 @@ jQuery.support = (function() {
 		}
 	}
 
+	support.clearCloneStyle = (function() {
+		var source = document.createElement( "div" ),
+			styleName = "backgroundClip",
+			value = "content-box",
+			clone;
+
+		source.style[ styleName ] = value;
+		clone = source.cloneNode( true );
+		clone.style[ styleName ] = "";
+
+		return source.style[ styleName ] === value;
+	})();
+
 	// Run tests that need a body at doc ready
 	jQuery(function() {
 		var container, div, tds, marginDiv,