<%@ Page Language="C#" %><%@ Implements Interface="System.Web.UI.ICallbackEventHandler" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"><script runat="server"> protected void Page_Load(object sender, EventArgs e)
{
string callback = this.ClientScript.GetCallbackEventReference(this, "this.value", "ProcessReverse", null); this.TextBox1.Attributes.Add("onchange", callback);
} string ICallbackEventHandler.RaiseCallbackEvent(string eventArgument) { char [] chars = eventArgument.ToCharArray(); Array.Reverse(chars); return new string(chars); }</script><html xmlns="http://www.w3.org/1999/xhtml" ><head id="Head1" runat="server"> <title>Untitled Page</title></head><body> <form id="form1" runat="server"> <div> <asp:TextBox ID="TextBox1" Runat="server"></asp:TextBox> </div> </form></body></html><script>function ProcessReverse(result,context){ alert(result) document.all.TextBox1.value = result;}</script>