<script runat="server">
Sub change(sender As Object, e As EventArgs)
lbl1.Text="You changed text to " & txt1.Text
End Sub
</script>
<!DOCTYPE html>
<html>
<body>
<form runat="server">
Change text
<asp:TextBox id="txt1" runat="server"
text="Hello World!" ontextchanged="change" autopostback="true"/>
<p><asp:Label id="lbl1" runat="server" /></p>
</form>
</body>
</html>