动态复选框列表取消选中所有javascript

Question

所有，我正在从数据库的第一个索引中加载一个值为“ ALL”的动态复选框列表。当0索引被选中时，所有其他复选框都需要取消选中。选中任何其他复选框时，需要取消选中“所有”。

    <asp:CheckBoxList ID="cblResponsibility" runat="server" DataTextField="description" DataValueField="code" 
                                                                                                            RepeatLayout="Table" RepeatDirection="Vertical" RepeatColumns="1" Font-Size="X-Small" AutoPostBack="false"  onclick="toggleResponsibilityCheckBoxes(this)">
                                                                                                        </asp:CheckBoxList>


<script type="text/javascript">  
        function toggleResponsibilityCheckBoxes(elem)
        {
            var div = document.getElementById('<% = cblResponsibility.ClientID%>');
            var chk = div.getElementsByTagName('input');
            var len = chk.length;
            var allChecked = false;
            var checkedcount = 0;
            for (var i = 0; i < len; i++)
            {
                if (chk[i].type === 'checkbox')
                {
                    if (chk[0].checked == true && i > 0 && allChecked==true)
                    {                       
                        chk[i].checked = false;                      
                    }
                    if (i != 0 && chk[i].checked == true)
                    {
                        allChecked = true;
                       // chk[0].checked = false;                       
                        checkedcount = checkedcount+1
                    }
                    if (len - 1 == checkedcount) {

                        for (var i = 1; i < len; i++)
                        {
                            chk[i].checked = false;
                        }
                        chk[0].checked = true
                    }
               }
            }
</script>