addClass doesn't fail when passed an undefined or null variable (#1309)

diff --git a/src/jquery/jquery.js b/src/jquery/jquery.js
index 741b13b..d6d3d6a 100644 (file)
--- a/src/jquery/jquery.js
+++ b/src/jquery/jquery.js
@@ -1365,7 +1365,7 @@ jQuery.extend({
        className: {
                // internal only, use addClass("class")
                add: function( elem, c ){
-                       jQuery.each( c.split(/\s+/), function(i, cur){
+                       jQuery.each( (c || "").split(/\s+/), function(i, cur){
                                if ( !jQuery.className.has( elem.className, cur ) )
                                        elem.className += ( elem.className ? " " : "" ) + cur;
                        });