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How to Limit Checkbox Selections in Fluent Forms

19 threads Sep 9, 2025

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One common challenge when building forms with Fluent Forms is controlling how many options a user can select from a checkbox field. Whether you're running a survey, a quiz, or a product selection form, you might need to enforce a limit, like "Choose up to 5 items." This guide will explain why this happens and provide the most common solution using custom JavaScript.

Why You Can't Limit Checkboxes by Default

Out of the box, the Fluent Forms checkbox field does not include a built-in setting to limit user selections. This is a design limitation of the plugin's free version. As seen in the community forums, this is a frequent user request, but it is not currently a standard feature on the development roadmap.

The Solution: Custom JavaScript Code

The most effective way to implement a selection limit is by adding a custom JavaScript code snippet to your form. This method provides a clean user experience by disabling further selections once the limit is reached.

Step-by-Step Implementation

  1. Add a Container Class: Edit your checkbox field in the Fluent Forms builder. In the Advanced Options tab, find the Container Class field. Enter a unique class name here, such as max_3_items. This class will be used to target your specific checkbox field.
  2. Add the JavaScript Code: Navigate to your form's settings. Find the Custom CSS and JS section and click on the Custom JS tab. Paste the following code snippet, adjusting the number 3 to your desired selection limit. 
    jQuery(document).on('fluentform_init', function ($) {
    jQuery('.max_3_items input[type="checkbox"]').on('change', function (evt) {
        var maxAllowed = 3;
        if (jQuery('.max_3_items input[type="checkbox"]:checked').length > maxAllowed) {
            this.checked = false;
            alert('You can only select a maximum of ' + maxAllowed + ' options.');
        }
    });
});
  3. Save and Test: Save your form and test it on the front end of your website. The script will now prevent users from checking more boxes than the limit you set.

Important Considerations

  • This solution requires basic comfort with editing form settings and adding code snippets.
  • The code uses the class max_3_items to identify your checkbox field. Ensure the class name in the code matches the one you added to your field exactly.
  • This is a front-end limitation. For mission-critical data validation, you should also implement back-end checks using Fluent Forms hooks.

While not a native feature, this JavaScript workaround is a powerful and reliable method for controlling checkbox selections in your Fluent Forms.

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