Merge pull request #1084 from execjosh/stop-also-at-root-element

Also stop at root when extracting CSS color

jquery.colorhelpers.js

@@ -74,13 +74,18 @@
     // if it's "transparent"
     $.color.extract = function (elem, css) {
         var c;
+        var parentElm;
         do {
             c = elem.css(css).toLowerCase();
             // keep going until we find an element that has color, or
-            // we hit the body
+            // we hit the body or root (have no parent)
             if (c != '' && c != 'transparent')
                 break;
-            elem = elem.parent();
+            parentElm = elem.parent();
+            if (null == parentElm.get(0)) {
+                break;
+            }
+            elem = parentElm;
         } while (!$.nodeName(elem.get(0), "body"));
 
         // catch Safari's way of signalling transparent