Understanding event.returnValue Deprecation Warning: Why and How to Fix?

jQuery: Understanding the Event.returnValue Deprecation Warning

Problem Statement

Consider the following jQuery script:

<code class="js">$(document).ready(function () {
    $("#changeResumeStatus").click(function () {
        $.get("{% url 'main:changeResumeStatus' %}", function (data) {
            if (data['message'] == 'hidden') {
                $("#resumeStatus").text("скрыто");
            } else {
                $("#resumeStatus").text("опубликовано");
            }
        }, "json");
    });
});</code>

Upon executing this script, you may encounter the warning in Google Chrome's console:

event.returnValue is deprecated. Please use the standard event.preventDefault() instead. 

Despite the error, your code will still function as expected.

Question

Why is this error occurring, and what is the necessary fix?

Answer

The error you're seeing is a deprecation warning, indicating that event.returnValue is no longer preferred and will eventually be removed in future versions. To prevent this error, you should use event.preventDefault() instead.

Solution

jQuery Version 1.10.2 and Earlier:

If you're using jQuery version 1.10.2 or earlier, you'll need to modify your code as follows:

<code class="js">$(document).ready(function () {
    $("#changeResumeStatus").click(function (event) {
        event.preventDefault(); // Prevent the default action
        $.get("{% url 'main:changeResumeStatus' %}", function (data) {
            if (data['message'] == 'hidden') {
                $("#resumeStatus").text("скрыто");
            } else {
                $("#resumeStatus").text("опубликовано");
            }
        }, "json");
    });
});</code>

jQuery Version 1.11 and Later:

If you're using jQuery 1.11 or later, the issue has already been addressed in the framework. Nonetheless, for clarity, here's the updated code:

<code class="js">$(document).ready(function () {
    $("#changeResumeStatus").click(function (event) {
        event.preventDefault(); // Prevent the default action
        $.get("{% url 'main:changeResumeStatus' %}", function (data) {
            if (data['message'] == 'hidden') {
                $("#resumeStatus").text("скрыто");
            } else {
                $("#resumeStatus").text("опубликовано");
            }
        }, "json");
    });
});</code>

With these modifications, you'll no longer encounter the deprecation warning, and your code will continue to function properly.

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