全选js代码：

<script>
    function CheckAll()  {
        var checkall=document.getElementById("chk");           //chk全选按钮的id
        var checkid=document.getElementsByName('counts[]');    //counts[]复选框的name
        if(checkall.checked==true){
            for(var i=0;i<checkid.length;i++){
                checkid[i].checked=true;
            }
        }else{
            for(var i=0;i<checkid.length;i++){
                checkid[i].checked=false;
            }
        }
    }
</script>