checkbox全选的设计

http://viralpatel.net/blogs/2010/11/multiple-checkbox-select-deselect-jquery-tutorial-example.html

<SCRIPT language="javascript">

$(function(){

 

    // add multiple select / deselect functionality

    $("#selectall").click(function () {

          $('.case').attr('checked', this.checked);

    });

 

    // if all checkbox are selected, check the selectall checkbox

    // and viceversa

    $(".case").click(function(){

 

        if($(".case").length == $(".case:checked").length) {

            $("#selectall").attr("checked", "checked");

        } else {

            $("#selectall").removeAttr("checked");

        }

 

    });

});

</SCRIPT>