Don't "lock" the submit button. Why? Because you are then using UI features I have no way to know about in advance. Simple HTML I can know about in advance b

Don't "lock" the submit button. Why? Because you are then using UI features I have no way to know about in advance. Simple HTML I can know about in advance but not what can be done with JavaScript, AJAX, etc. So, don't implement new, unique UI features.