I am using the Samsung Galaxy s3 v4.1.2 and it used default android stock browser, and for the embedded webview component as well.
The stock browser just failed to hide the form and show the loading div block, Button are disabled sometime and sometime not. But when I clicked back button, the loading div is displayed.
The best way to ensure submit button is disabled is actually to hide it by coding it in the html (old school method) rather in jquery.
However, the previous way works well on a nexus device which used chrome as default browser. It works on ios devices too.
<input type="submit" name="submit" value="Confirm" onclick="this.style.visibility='hidden'"/>