[krutoy]

кто сказал что не работает?

<form id="formID" action="http://ya.ru">
<input type="submit">
</form>
 
<script>

var form = document.getElementById('formID');
form.addEventListener("submit", function() {
return false
});

<form id="formID" action="http://ya.ru">
<input type="submit">
</form>
<script>
var form = document.getElementById('formID');
form.onsubmit = function () {
return false
}
</script>