Double Submit Prevention

Fix a form that can be submitted multiple times by disabling the submit button immediately on the first click.

The bug allows users to click submit several times, sending duplicate requests. Implement logic to disable the button right after the first click and prevent further submissions.

Add a handler that disables the button and changes its state (e.g., text to "Submitting...") on the first submission. Re-enable it if the submission fails.

Guard against double-click and Enter-key double submission.

Test that only one submission occurs even with rapid clicks.