js 删除DropDownList的选项

function del_DropDownList_Option() {
            var   ddlXZ=  document.getElementById("name");
            var i = ddlXZ.length - 1;
            if (i > -1) {
                ddlXZ.remove(i);
            }
            else {
                alert("DropDownList为空")
            }
        }