I found this solution that is simple and worked for me:
<form ...>
<input ...>
<button ... onclick="this.disabled=true;this.value="Submitting..."; this.form.submit();">
</form>
This solution was found in:
Original solution
I found this solution that is simple and worked for me:
<form ...>
<input ...>
<button ... onclick="this.disabled=true;this.value="Submitting..."; this.form.submit();">
</form>
This solution was found in:
Original solution