Greeting to everyone.

I began working on Javascript about 3 day ago and im stuck on forms and submiting of them. I'm using 'Learnin JavaScript' by o'Reilley and in there is this example (not the same but it works the same)...


Code JavaScript:
 
window.onload = execute;
 
var setup = {
   catchEvent : function(eventObj, event, eventHandler) {
      eventObj.addEventListener(event, eventHandler, false); 
   },
 
   cancelEvent : function(event) {
      if(event.preventDefault) {
	     event.preventDefault();
		 event.stopPropagation();
	  }
   }
}
 
function formSetup(evn) {
   var options = document.exp_form.mjesto.options;
 
   for(var i = 0; i < options.length; i++) {
      if(options[i].selected) {
	     console.log('You have selected ' + options[i].text);
	  }
   }
 
   return false;
}
 
function execute() {
   setup.catchEvent(document.exp_form, 'submit', formSetup);
}

So, the event gets added to the form the minute the page loads. The function loaded is formSetup but the form doesn't enter in that function. If i put an alert(), its not executed. formSetup() function is not binded with the event, but why?