Apart from what others have said, you can also try to use Ajax requests to submit the form, this way you will be able to send the details to server and browser won't intervene here.
$.ajax({
data: {
uname: $('#username').val(),
upass: $('#pass').val()
},
success: function(response) {
}
});
Notice that I used IDs, instead of native
type checking selection, this one looks clean. But this is just a quick hack and may not work in later versions of browsers. Also, this does not mean any plugins won't notice this.
Even this method fails sometime if you use POST requests with username/password to submit forms. I happen to see "Save password" dialog on Chrome (Firefox would do the same) for my Azure VMs, where page reloading and conventional submission is not at all a problem.
So, as mentioned in comments it is entirely in the hands of user.