后端：页面需继承ICallbackEventHandler
protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { string strRefrence = string.Empty; strRefrence = Page.ClientScript.GetCallbackEventReference(this, "arg", "ReceiveDataFromServer", "context"); // 这里ReceiveDataFromServer为客户端接收回调结果的JS方法，含一个传入参数 string strCallBack = string.Empty; strCallBack = "function CallBackToTheServer(arg, context) {" + strRefrence + "};"; Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "CallBackToTheServer", strCallBack, true); // CallBackToTheServer，JS方法，发出回调请求 } } #region ICallbackEventHandler Members private string strTimeFormat; public string GetCallbackResult() { if (strTimeFormat != "" && strTimeFormat == "12") { return DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss（12小时制）"); } else { return DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss（24小时制）"); } } public void RaiseCallbackEvent(string eventArgument) { strTimeFormat = eventArgument; } #endregion
前端：
<html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <script> function ReceiveDataFromServer(valueReturnFromServer) { document.getElementById("ServerTime").innerHTML = valueReturnFromServer; } function GetServerTime(format) { CallBackToTheServer(format, ""); } </script> <title></title> </head> <body> <form id="form1" runat="server"> <div> <asp:Button ID="btnShow12" runat="server" Text="获取服务器时间（12小时制）" OnClientClick="javascript:GetServerTime(12);return false;" /><br /> <asp:Button ID="btnShow24" runat="server" Text="获取服务器时间（24小时制）" OnClientClick="javascript:GetServerTime(24);return false;" /><br /> <br /> <span id="ServerTime"><%= DateTime.Now.ToString("yyyy-MM-dd HHHH:mm:ss") %></span> </div> </form> </body> </html>