>>>>I couldn't get this to work. I do see the script is injected when I look in firebug but I also see when I drill down the button ID is a long name starting with ctl00_ctl00_Retirement Management System_cphOuterContent_cphMainContent_RightContent_ctrlAgreement_btnAgreeContinue
>>>>
>>>>Can that have anything to do with it?
>>>
>>>Well the string in getElementById() in the script obviously has to match to actual Id of the button in question. Can't you just give the button a specific (short) Id ?
>>
>>Yep, my button ID is as above, but it doesn't show up that way in firebug. The button is in a Web User Control which is added to a content page that is in a nested master. I would guess it gets altered when it is dynamically added. I do have a routine for getting the id of a control, maybe I need to obtain that in code and alter the code to pass that in.
>
>Sorry, I'd forgotten about that behaviour. I guess, if the checkbox and button are at the same level then this would work in the function:

var s = checkbox.id.substr(0, checkbox.id.lastIndexOf("_") + 1) + "btnAgreeContinue"; ;
>var button = document.getElementById(s);
>button.disabled = !checkbox.checked;

but there must be something a bit more elegant.....


This didn't work either. I tried my other code to FindControl and pass that in such as this so I could see what the button id was and surprising it is 'btnContinue". So very frustrating to get such a simple thing to work. These things make me want to stick to WPF or Silverlight and avoid ASP.net.
Tim

mmButton thisButton = (mmButton)this.FindControlByName(this, "btnAgreeContinue");

StringBuilder sb = new StringBuilder();
sb.Append(@"<script language='javascript' type='text/javascript'>");
sb.Append(@"function SetAgreeAndContinue(checkbox) {");
sb.Append(@"var button = document.getElementById('" + thisButton.ID + "');");
sb.Append(@"button.disabled = !checkbox.checked;");
sb.Append(@"}");
sb.Append(@"</script>");

string myscript = sb.ToString();
Page.RegisterStartupScript("S", myscript);