The error message “uncaught referenceerror: $ is not defined” is frequently encountered by developers in JavaScript, causing confusion and frustration.
It is essential for creating reliable and bug-free web applications to comprehend the underlying cause of this error and learn effective approaches to resolve it.
For that reason, this article aims to delve into the reasons behind the “$ is not defined” error and offer practical solutions to overcome it.
What is Uncaught Referenceerror: $ is not defined
The error “Uncaught ReferenceError: $ is not defined” typically occurs in JavaScript code. It indicates that the symbol “$” is being used as a variable or function name, but it has not been defined or imported properly.
In JavaScript, the symbol “$” is commonly associated with popular libraries like jQuery.
In fact, many JavaScript libraries use the “$” as a shorthand for accessing their functionality.
However, in order to use these libraries, you need to ensure that they are properly loaded and available in your code.
Common cases referenceerror: $ is not defined occur
Here are the common cases why this error occurs:
📌 The path to your jQuery.js file is incorrect or unavailable, resulting in an Error 404 indicating that the file cannot be found.
<script src="/wrong/path-to/jquery.min.js"></script>
To resolve the issue, you should fix the path to the jQuery.js file in your project.
If your project is a public website, it is recommended to use the Google hosted jQuery file.
This ensures that the file is readily available and accessible for your website visitors.
<script src="/correct/path-to/jquery.min.js"></script>
📌 jQuery plugin is included before jQuery file.
<script src="/path-to/jquery.plugin.js"></script> <script src="/path-to/jquery.min.js"></script>
Ensure that you include the jQuery.js file before any jQuery plugin files in your code.
<script src="/path-to/jquery.min.js"></script>
<script src="/path-to/jquery.plugin.js"></script>📌 You are including jQuery file without the protocol in the URL and accessing the page from your local file system.
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
Temporarily add HTTP protocol (http:// instead of //) in the URL while you are developing.
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>📌 jQuery file is included from the web, but you don’t have an internet connection. It is a silly mistake, but you would be surprised how ofter it happens.
<script src="http://www.example.com/js/jquery.min.js"></script>
Include local jquery.js file copy or connect to the internet
<script src="/js/jquery.min.js"></script>
How to fix uncaught referenceerror: $ is not defined
So here are the recommended fix you can try in fixing the error.
- Ensure jQuery is included
If you’re using the “$” symbol as a shorthand for jQuery, make sure you have included the jQuery library before using it
You can do this by adding the following script tag in the section of your HTML file:
This will load the jQuery library from a CDN (Content Delivery Network). Adjust the version number if needed. - Check script loading order
Verify that the script tag referencing jQuery is placed before the script where you’re using the “$” symbol.
The jQuery library needs to be loaded before you can use it.
For example:
- Use a different symbol:
If you suspect a conflict with other libraries or frameworks, you can try using a different symbol instead of “$” for jQuery.
You can achieve this by utilizing the jQuery.noConflict() method.
For example:
- Check for conflicts:
Ensure that there are no other libraries or scripts that are overriding the “$” symbol. Some JavaScript frameworks or libraries may use “$” as well.
In such cases, you can use an IIFE (Immediately Invoked Function Expression) to create a local scope and pass the jQuery object as a parameter.
This way, you can use a different symbol within your code.
Example:
- Verify file paths and dependencies:
Double-check that the paths to the jQuery library and other dependencies are correct.
Ensure that the file names and paths are accurate, and the required scripts are properly included.
Anyway, here are other fixed errors you can refer to when you might encounter them.
Conclusion
In conclusion, the “uncaught referenceerror: $ is not defined” error is a common challenge for JavaScript developers. By understanding its causes and implementing the discussed solutions, you can effectively overcome this error and ensure smooth JavaScript code execution.
Remember to correctly include the jQuery library, manage script loading order, resolve conflicts, and verify variable and function references.
We hope this guide has assisted you in resolving the error effectively.
Until next time! 😊