Event.observe(window, 'load', function() {
  Event.observe('form', 'submit', checkForm);
});

/** 
 Function to prevent home page form from being submitted
 unless application type has been selected.
 
 @param event e 
**/
function checkForm(e) {
  try {
    var app_type = $$('input[name=application_type]:checked').first();
    //Stop form submission and provide validation message
    if(!app_type) {
      Event.stop(e);
      alert('Please select an application type.');
    }
  }
  catch(err) {
    Event.stop(e);    
  }   
}