织梦后台自定义表单添加全选/全不选功能按钮

<label><input type="button" name="select" onClick="selAll()" value="全选"/></label>
<label><input type="button" name="select" onClick="noSelAll()" value="反选"/></label>
<script type="text/javascript">
function selAll(){
    var a = document.getElementsByTagName("input");
    for(var i = 0;i<a.length;i++){
        if(a[i].type == "checkbox") a[i].checked = true;
    }
}
function noSelAll(){
    var a = document.getElementsByTagName("input");
    for(var i = 0;i<a.length;i++){
        if(a[i].type == "checkbox") a[i].checked = false;
    }
}
</script>