enable textbox with checkbox checked with javascript

[caddyman]

HEllo - I am trying to enable/disable textbox when checkbox is checked (enable) or unchecked (disable). WIth the piece of code i have nothing is happening once the checkbox is checked/unchecked. Here is what I have:\[code\]<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="AssociationInfo.ascx.cs" Inherits="Administration.Modules.AssociationInfo" %><%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %> <script type="text/javascript" language="javascript"> function enableTextBox() { window.onload = function () { var check = document.getElementById("chkAssociation"); check.onchange = function () { if (this.checked == true) document.getElementById("txtAddress").disabled = false; else document.getElementById("txtAddress").disabled = true; }; }; } </script> <div> <h2>Association Info</h2> <br /> <asp:CheckBox Checked="false" ID="chkAssociation" runat="server" />&nbsp;&nbsp; <asp:TextBox ID="txtAddress" Text="Test" runat="server" /> </div>\[/code\]The code is in web user control. Could that be reason why is not working correctly?Thanks for helpingThanks everyone for the help in advance, Laziale