moss后台加javascript

 if (this.ActivityStartTime.SelectedDate > this.ActivityEndTime.SelectedDate)
                {
                    Page.ClientScript.RegisterStartupScript(typeof(string), "alertKey", string.Format("<script type=\"text/javascript\" language=\"javascript\">alert('{0}');</script>", "活动结束时间必须大于等于活动开始时间!"));
                    return;
                }