Example of overwritten form.submit
HTML
<form>
<input id="submit">
</form>
<form></form>
<pre id="target"></pre>
CSS
/* see http://stackoverflow.com/questions/22868547/form-submit-is-not-found-in-javascript */
JavaScript
document.getElementById('target').innerHTML =
document.forms[0].submit.toString() +
"\n\n" +
document.forms[1].submit.toString();