ASP.NET Terms and Conditions, Disable Button till scroll down

Hey I have a Terms and Conditions Text area which has a scroll bar and a normal ASP.NET button below that.

I was wondering how could I disable this button till the user scro开发者_运维百科ll till the end of terms and conditions.

This is something that's best accomplished client-side - are you already using a library such as jQuery or something else?

Setting up the following works a treat:

<asp:TextBox runat="server" id="termsConditions" 
             TextMode="MultiLine" Rows="10" Columns="50">
  Lots of text here[...]
</asp:textbox>
<asp:button runat="server" id="accept" text="Accept" />

<script type="text/javascript">
  // Using jQuery, other options are available

  // pick up the button, and disable it, keeping the button for later.
  // Note the use of the ClientID property of the ASP.NET controls - this allows
  // us to cleanly pick up the client side id of the objects.
  var button = $("#<%= accept.ClientID %>");
  button.attr("disabled", "disabled");

  // pick up the textarea.
  var terms = $("#<%= termsConditions.ClientID %>");

  // bind to the textarea's scroll event
  terms.scroll(
   function () {
     // Compare the scollHeight (the complete height of the textarea), with the
     // combination of the current position (scrollTop) and the offsetHeight.
     if (terms[0].scrollHeight < (terms[0].offsetHeight + terms[0].scrollTop)) {
       // Re-enable the button
       button.attr("disabled", null);
     }
   });
</script>

ours is not to reason why, here's an example

http://www.27seconds.com/kb/article_view.aspx?id=56