function onChecked(element, dropdownid)
{
    if(element!=null)
    {
        if(element.id == "optSearch_0")
        {
            if(element.checked)
            { 
                document.forms[0].optSearch_0.checked=true;
                document.forms[0].optSearch_1.checked=false;
                var dropdown = document.getElementById(dropdownid);
                if(dropdown != null)
                    {dropdown.disabled=true;}
                                
                }
        }
        else if(element.id == "optSearch_1")
        {
            if(element.checked)
            {
                document.forms[0].optSearch_0.checked=false;
                document.forms[0].optSearch_1.checked=true;
                var dropdown = document.getElementById(dropdownid);
                if(dropdown != null)
                    {dropdown.disabled=false;}

             }
             else
             {
                var dropdown = document.getElementById(dropdownid);
                if(dropdown != null)
                    {dropdown.disabled=true;}
             }
         }
        
    }
}