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;
});