[jQuery] disable select in FF?

[alivemedia]

I am trying to disable / enable a select drop down list.  Works fine
in IE but not in FF.  I have a check box that when checked the select
becomes enabled when unchecked then it become disabeled.  Here is my
code:

$('input[type=checkbox]').bind("click",function(){
            var el=$(this).parent().next('td select')
            if (this.checked) {
                el.removeAttr("disabled");
                 el.attr("enabled","enabled");
            } else {
              el.removeAttr("enabled");
                el.attr("disabled","disabled");
            }
        }).each(function(){ var el=$(this).parent().next('td select');
        if (this.checked) {
                el.removeAttr("disabled");
                 el.attr("enabled","enabled");
            } else {
              el.removeAttr("enabled");
                el.attr("disabled","disabled");
            }
         });

thanks for any help!!!