Uncaught ReferenceError: $ is not defined

If you’re encountering an error message like “Uncaught ReferenceError: $ is not defined” in your JavaScript code, it usually means that the JavaScript interpreter doesn’t recognize the “$” symbol. This often occurs in the context of jQuery, where the “$” is used as a shortcut to access jQuery functions.

Here are some common reasons why “$” might not be found:

1. jQuery is not Loaded: The most common reason is that jQuery library is not loaded at the time your script is trying to use $. Make sure that you have included the jQuery library and it is loaded before you use “$” in your script.
2. Multiple jQuery Versions: If you’re using more than one jQuery version on the same page, they could be conflicting with each other. Make sure you’re only loading one version of jQuery.
3. Conflict with Other Libraries: If you’re using other JavaScript libraries that use the “$” symbol, such as Prototype or MooTools, this could cause conflicts. In this case, you can use jQuery’s noConflict() method to give control of the “$” variable back to the other library and use a different alias for jQuery.
4. Scope Issues: If you’re using jQuery inside a function or a block, make sure that it is accessible in that scope. For example, if you’re using a module system like CommonJS or AMD, you might need to import jQuery in every module where it is used.
5. Incorrectly Formatted Document Ready Function: If you’re trying to execute jQuery code before the document is fully loaded, it might fail because the elements it is trying to access are not available yet. Always wrap your jQuery code inside a $(document).ready() function to ensure the entire page is loaded before the script runs.

//we utilize JavaScript, just in case jQuery hasn't loaded yet.
document.addEventListener("DOMContentLoaded", function() {
    //We define $ for applications that do not have it defined (Like WordPress)
    var $ = jQuery;
    // Your code here
});

These are some common issues that could lead to “$ is not defined” errors when using jQuery. To troubleshoot, you need to carefully check your code and your environment to make sure jQuery is correctly loaded, isn’t conflicting with anything else, and is being used in the right way.