1<form method="POST">
2<input type="submit" formaction="default_url_when_press_enter" style="visibility: hidden; display: none;">
3<!-- all your inputs -->
4<input><input><input>
5<!-- all your inputs -->
6<button formaction="action1">Action1</button>
7<button formaction="action2">Action2</button>
8<input type="submit" value="Default Action">
9</form>