JS的全选与删除

<!--按钮全选与取消-->
        var checkflag="false";
function check(field){
        field = document.getElementsByName(field)
        if(checkflag=="false"){
                for(i=0;i<field.length;i++)
                {
                        field[i].checked = true;
                }
                checkflag="true";
                return "取消选定";
        }
        else {
                for(i=0;i<field.length;i++)
                {
                        field[i].checked = false;
                }
                checkflag="false";
                return "全部选定";
        }
}

<!-- 判断是否被选中（函数型）-->
function del(path,obj) {//删除
if(confirm("确实要删除吗？")){
    var n = 0;
    for (var i = 0; i < document.all(obj).length; i++) {
        var e = selectForm.elements[i];
        if (e.checked == true) {
            ++n;
            }
        }
        if (n == 0) {
                alert("您还没有选择要删除选项！");
            return false;
        } else {
            var id = "";
            for (var i = 0; i < document.all(obj).length; i++) {
                var e = selectForm.elements[i];
                if (e.checked == true) {
                    id += e.value+",";
                }
            }
            document.location.href = path+id;
        }
     }
}

<!--
    onClick="del('admin/toDeleteSelectUser.action?ids=','mm')"
    <input type="checkbox" name="mm" value="<c:out value='${userList.id}'></c:out>">
    -->