prototype javascript library Form observe example

<form action="event_observe_submit" method="post" id="f1" name="form_name" accept-charset="utf-8">
 <p><input type="text" id="t1" name="t1" value="Continue">text</p> 
 <p><input type="text" id="t2" name="t2" value="Continue">text</p>
 <p><input type="checkbox" id="c1" name="cb[]" checked>checkbox</p> 
 <p><input type="checkbox" id="c2" name="cb[]">checkbox</p> 
 <p><input type="submit" id="s1" name="submit" value="Continue"></p>
</form>
<script type="text/javascript" charset="utf-8">
//new Field.EventObserver('t1', function (args) { alert(args + args.value); });
//new Field.EventObserver('c1', function (args) { alert(args + args.value); });
new Form.EventObserver('f1', function (args) { alert(args + args.value); });
</script>