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Avoiding $()slick is not a function Error: Guidelines for Correct Script Loading

In today’s internet-dependent world, web development has become an essential aspect of business. However, performing website maintenance requires a fair understanding of the different libraries, functions, and their compatibility with various browsers.

This is especially true for the various JavaScript libraries, including jQuery and Slick, that web developers use to add interactivity and visual aesthetics to websites. Two common issues faced when working with these libraries are errors and incorrect script loading.

This article aims to provide developers with guidelines to correctly handle these issues when they arise. Part 1: Handling the “$(…).slick is not a function” jQuery error

Reasons for the error

Step one in solving an error is to understand the possible reasons it occurred. In this case, “$(…).slick is not a function” error occurs when the Slick library is not loaded correctly.

This error could arise due to multiple reasons:

– The path to the Slick library is incorrect, which can occur if the file was moved to another directory or renamed. – The Slick library was not loaded before the script that requires it.

– Multiple instances of jQuery library are loading on the same page, which could lead to conflict between different versions

Solution for the error

There are several solutions to the “$(…).slick is not a function” error:

Load order: Ensure that the Slick library and jQuery library are loaded in the correct order. Slick must be loaded after jQuery.

To load both libraries, use the correct URLs, and reference them in your HTML file. “`


Multiple Loading: Check for instances of multiple loading of the libraries.

This can occur when referencing the libraries in different JavaScript files. Ensure to remove the redundant reference to the jQuery or Slick library.



404 errors: Check for 404 (file not found) errors in the console. This error can occur if the Slick library or the jQuery library is not present in the specified path.


Failed to load resource: the server responded with a status of 404 (Not Found)


Recent versions: Ensure that you are using up-to-date versions of the jQuery and Slick libraries. Newer versions of these libraries often have bug fixes that could solve the error.

Part 2: Loading the necessary scripts correctly

Importance of script loading order

When working with multiple scripts, it is essential to pay attention to the order of loading. Ideally, the cascading style sheet (CSS) should be loaded first to provide an initial look to the web page.

The Slick library and the jQuery library should then follow the CSS. The index.js file should be loaded after the Slick and jQuery libraries for scripts to take advantage of the functions and interactions provided by them.

Example of correct script loading order

The correct order for loading scripts is as follows:



Checking for correct script loading

To ensure that all scripts are loaded correctly, use the developer tools that come with most web browsers. From this tool, navigate to the Console tab, and check for any errors that may have occurred.

If there are no errors, expand the loaded files section to see which scripts were loaded and in what order. If all loading is successful, you will see a message like “All files were loaded successfully” from the browser console.

Understanding script loading and elimination of errors helps to ensure that a website is performing optimally. Identifying and solving these issues quickly could save you time, resources, and a poor user experience for website visitors.

With this knowledge, we empower website developers to work more efficiently and effectively, ensuring that websites operate optimally and meet the expectations of their clients and users. Part 3: Final Considerations for Avoiding the Error

To ensure that your website runs smoothly, there are a few final considerations to prevent the “$(…).slick is not a function” error.

Avoiding loading jQuery library twice

Loading jQuery library twice is a common mistake that web developers often make, which may lead to conflicts with other scripts on a page. The best practice is to reference the library once and use it wherever it is required.

If the library has already been loaded by a third-party script, you can check if it exists before running your code. You can use the following code to check for the librarys existence:


if (typeof jQuery == ‘undefined’) {

// jQuery library doesn’t exist

} else {

// jQuery library exists



Using recent versions of libraries

Using up-to-date libraries is vital to avoiding conflicts and ensuring optimal performance. Developers should regularly check for updates to libraries used in their websites.

In the case of jQuery and the Slick library, updates often include new features, bug fixes, and security patches. Use the latest version of each library to ensure an optimal web development experience and to keep your website secure.

Recap of solution for the error

The “$(…).slick is not a function” error can be quite frustrating, but following these guidelines can help you to resolve the issue:

First, ensure that the Slick library and the jQuery library are loaded correctly and in the correct order. Slick must follow jQuery, and you should reference them correctly in your HTML file.

Check for cases of multiple loading, 404 errors, or outdated versions of the libraries. Second, with multiple scripts on a page, script loading order is essential.

You should load CSS first, followed by the Slick and jQuery libraries, before finishing with the index.js file. Finally, for further optimization, avoid loading the jQuery library twice within the same page and use recent versions of libraries whenever possible.


In conclusion, web development is a continually evolving field. Though exciting with unique possibilities, it comes with its fair share of technical challenges, like the “$(…).slick is not a function” error.

Maintaining awareness of script loading order and library updates can help you to avoid common errors, resolve issues quickly, and improve website performance. The guidelines provided in this article present an excellent starting point to keep your site both functional and visually appealing while providing an optimal user experience.

In summary, this article provides guidelines for web developers to avoid common issues with the Slick and jQuery libraries. The “$(…).slick is not a function” error can occur due to incorrect script loading and outdated library versions.

To prevent this error, developers should ensure proper script loading order, avoid loading libraries twice, and use updated versions of libraries. By taking these steps, web developers can ensure better website performance and user experience.

The importance of maintaining awareness of these issues is crucial in the ever-evolving field of web development, where efficient and error-free websites can make all the difference. Remember to follow these simple steps to avoid these issues and ensure optimal website performance.

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