在后台 .cs 中执行前台的js 函数

        <script type="text/javascript" language="javascript"> 
<!--
    function openChild(num, num2) {

        var k = window.showModalDialog("pop.aspx?userid=" + num + "&usertel=" + num2, window, "dialogWidth:808px;status:no;dialogHeight:540px");
        if (k == 1)//判断是否刷新 
        {
            alert('刷新');
            window.location.reload();
        }
    }
  
    //--> 
</script> 

.cs

 protected void Button1_Click(object sender, EventArgs e)
        {
            string isFresh = "1";
            string script = string.Format("openChild('{0}', '{1}');", isFresh, "13943288280");
            ScriptManager.RegisterStartupScript(this, this.GetType(), "Message", script, true);
        }