Call 'disableDuplicateSubmit' method on form to prevent to be duplicate submitted.
$('form').disableDuplicateSubmit();
Add 'prevent' class to submit button.
<button type='submit' class='prevent'>Submit</button>
Submit button should be in the same context with form.
For example, this case doesn't work.
<div>
<form> <-- This should be placed BEFORE div tag
<button type="submit" class="prevent">Button</button>
</div>
</form>