function gotoLink(form) {
   var OptionIndex=form.ListBoxURL.selectedIndex;
   var comparevalue = new String(form.ListBoxURL.options[OptionIndex].value);
   x = comparevalue.substr(0,10);
   var vURL = new String("http://www");

   if (form.ListBoxURL.options[OptionIndex].value == "" || vURL.toLowerCase() != x.toLowerCase()) { 
                       
                          alert("Please choose a subject under this heading"); 
                     
                       }
                       else
                          {parent.location = form.ListBoxURL.options[OptionIndex].value;
                         }
                  }   //end