Hide control in ascx.

I have a user control in an ASP.net page that I add dynamically. I need to hide another control in the user control based on a radiobutton in that same user control.

I am using a javascript function to do so. The function fires (my alert works), but the control does not get hidden. Any idea why?

function YesChecked() 
    {
        alert('whee');
        document.getElementById("ctl00_ContentPlaceHolder1_ctl40_lblMatchingFormula").style.display = "none";
    }

Select allOpen in new window