How to Prevent Duplicate Form Submissions in Contact Form 7 Using JavaScript

The Problem: Why It Happens

If a user taps the submit button again before the first form finishes processing on your WordPress site, you will likely end up with multiple submissions cluttering inboxes, CRMs, or databases. This usually happens when:

• Forms are inside modals or tabs.

• The response is slow or unclear.

• There’s no feedback that the form is processing.

Preventing extra clicks is the key to keeping your submissions clean.

How to Diagnose It

✅ Confirm your form is using Contact Form 7.
✅ Check if it’s embedded in modals, popups, or tabs.
✅ Test: Click multiple times. Do you receive multiple emails or database entries?

If yes—it’s time to fix it.

The Fix: One Line of Defense

1️⃣ Leverage CF7’s Built-In Events

‍Contact Form 7 provides JavaScript events that trigger at specific points. We’ll use because it only fires after a successful form submission or validation success.

2️⃣ Target the Form Intelligently

‍Instead of relying on fixed IDs, use a wrapper like #cform so your code is flexible and won’t break when forms or input fields change in your WordPress site.

3️⃣ The Script:

document.addEventListener(‘wpcf7mailsent’, function (event) {

 if (event.target.closest(‘#cform’)) {

   const submitButton = event.target.querySelector(‘input[type=”submit”]’);

   if (submitButton) {

     submitButton.disabled = true;

   }

 }

}, false);

4️⃣ Why This Method Works

‍Using ensures that the button only disables after a successful submission—not before validation, like the event would. That way, you don’t accidentally block valid form attempts or cause an error in sending emails or storing input in the database.

What You’ll Achieve

✅ Better UX for your visitors.
✅ Clean, single submissions in your inbox.
✅ No more spammy duplicates.

Need help improving your WordPress forms or custom workflows? We build

 

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Frequently Asked Questions (How to Prevent Duplicate Form Submissions in Contact Form 7 Using JavaScript)

How does contact form 7 prevent duplicate submissions?

Contact Form 7 prevents duplicate submissions by using AJAX-based form handling, nonce security tokens, and disabling the submit button after click. It also relies on browser sessions and server-side validation to block repeated or accidental resubmissions of the same form data.

How to prevent multiple form submissions in JavaScript?

You can prevent multiple form submissions in JavaScript by disabling the submit button after the first click, using a flag variable to block repeated submits, handling the submit event properly, and re-enabling the button only after the form process or response is complete.

How do I restrict duplicate entries in Google Forms?

You can restrict duplicate entries in Google Forms by enabling “Limit to 1 response”, which requires users to sign in with a Google account. You can also use response validation, add unique fields like email, or manage duplicates later using Google Sheets formulas or add-ons.

How to prevent double click in JS?

You can prevent double click in JavaScript by disabling the button immediately after the first click, using a boolean flag to ignore repeated clicks, applying debounce or throttle functions, and re-enabling the button only after the action or process is successfully completed.