User283571144 posted
Hi Quick_Question_:
According to your codes, I found you use onChange attribute.
But the asp textbox control doesn't contain the onChange attribute, it only contains the OnTextChanged event.
I suggest you could use OnTextChanged event instead of onchange.
More details, you could refer to below test demo codes:
Notice: This event will be fried when losing focus on the textbox.
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="TextBoxChangedEventTest.aspx.cs" Inherits="AspNetNormalIssue.Webform.TextBoxChangedEventTest" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Textbox id="myTextbox" runat="server" OnTextChanged="txtChanged" AutoPostBack="true"/>
</div>
</form>
</body>
</html>
Code-behind:
using System;
using System.Diagnostics;
namespace AspNetNormalIssue.Webform
{
public partial class TextBoxChangedEventTest : System.Web.UI.Page
{
public void txtChanged(Object sender, EventArgs e)
{
Debug.WriteLine("Item changed");
Response.Write("Item changed");
}
protected void Page_Load(object sender, EventArgs e)
{
}
}
}
Result:

Best Regards,
Brando