判断select中是否有重复中的值

var tblusergroup="";var value="";var cf=true;$("#tblusergroup option").each(function(){value=$(this).val();if($("#tblusergroup option[value='"+value+"']").size()>1){cf=false;return;}else{tblusergroup+=$(this).val()+",";}        });if(!cf){jAlert("组内用户有重复","提示信息");        return;}