Vijay Singh Khatri | 08 Aug, 2023

Wordpress Javascript: What You Need to Know


Javascript is a very well-established front-end language used to add animation effects and styling onto a webpage. It does not run on the server, but actually on the user’s browser. Javascript has always been a part of Wordpress. The js folder in wp-admin and wp-includes stands for Javascript, mostly used for theme development. Now, with new interfaces, onboard such as Calypso, the role of Javascript has penetrated deeper. Javascript has an ecosystem of its own. AngularJS, jQuery, and Node.js are three standard terms that are associated with Javascript. But all the three entities are very different from each other. AngularJS is a Javascript Framework, while JQuery is a Javascript Library and Node.js, a runtime environment. However, over AngularJS, React has been more popular with the designers. 

The choice of Libraries and Frameworks should be based on needs. Wordpress development can be split into backend and frontend. Front-end developers should find it sufficient to proceed with AngularJS, Backbone.js, or React. For backend developers, preferably who are assumed to be well-versed in PHP, Node.js. For a Wordpress developer, it is not mandatory to know everything about Javascript. Javascript comes tied up with Wordpress in the form of numerous Javascript Libraries such as JSON, JQuery, Underscore.js, and Backbone.js. JQuery is an excellent place to begin. It makes programming with Javascript easier. Every interaction made through the admin screen in Wordpress happens through Javascript. It is only after clicking the Publish, Save Changes, or Update buttons that PHP comes into action, and changes are made onto the database. 

Besides being used to alter the existing HTML and CSS of a website, Javascript can be used for:

  • Events execution.
  • Validating input values and form submission.
  • Third-Party APIs.
  • Gathering User Data.
  • Loading Images Quickly.
  • Include Audio-Video Players
  • Respond to Mobile devices.

There are several ways to add Javascript to Wordpress. One such process is known as enqueueing. It is a CMS friendly way of adding scripts into Wordpress Websites. It prevents multiple additions of the same script. It manages script dependencies very efficiently. A point to be noted in this context is that as JQuery is enqueued already within Wordpress, it is not required to be enqueued again. The required scripts can be enqueued, and their dependency set to JQuery.

In order to enqueue scripts, the function wp_enqueue_script() needs to be used. It should be placed inside the function and then hooked to the wp_enqueue_script hook. If you need to load the script onto the admin screens, you use the same function, but you need to hook the function to admin_enqueue_styles hook. The WP-REST API enables you to interact with the website’s database. It is done using JSON. It reads, writes, and edits data using Javascript. 

There is always an occasional requirement to add additional tweaks beyond those allowed by the theme. Sometimes adding codes directly into a page may not be that easy. Javascript effects can then be added via plugins and themes

Several Plugins can be used to deploy scripts in a Wordpress Website. 

1. Insert Headers and Footers

This can be considered as one of the easiest ways to integrate third-party APIs. This does not require editing the existing theme directly. Its main features are:

  1. Ability to insert the code in either the header or the footer.
  2. Ability to add Google Analytics to any theme
  3. A one-stop script editing and insertion
  4. Insert Facebook Pixel code, add Google Analytics code to any theme. 
  5. Add custom CSS to any theme.
  6. Works with multiple kinds of code, including HTML, CSS, and Javascript


  1. Upload the insert-headers-and-footers directory to the /wp-content/plugins/ directory.
  2. Activate it through the Plugins Menu in Wordpress.
  3. Goto Setting > Insert Headers and Footers menu and start inserting your required code.

2. CSS and Javascript Toolbox(CJT)

It comes with a dashboard that enables you to manage all your website codes and snippets. It is effortless to work with. The custom codes can be added directly into unique CJT code blocks and assigned where required. Code block shortcodes provide further placement accuracy. Its main features are:

  1. Ability to add CSS, Javascript, HTML, and PHP to pages, posts, categories, etc.
  2. Ability to add front-end style without editing theme files
  3. Ability to manage all code additions through the dashboard Avoids the use of FTP
  4. Ability to add codes without the need to tweak core files.
  5. Enables code embedding via GitHub, CodeCanyon, and more
  6. Ability to add advertising, affiliate scripts, visitor tracking, marketplace store widgets, and social media channels
  7. CJT Plus comes with more options and more tools. It enables the addition of CJT code blocks as a Gutenberg Block. 
  8. Code injection via CJT Shortcodes, CJT Metabox Code Blocks, and CJT Widgets for sidebar or Footer.
  9. Beautify options for code optimization for better readability.
  10. Minify option for compressing codes to boost performance
  11. Code auto-completion feature
  12. A quick pagination dropdown selector to manage a website with thousands of posts.


  1. Upload css-javascript-toolbox folder to the /wp-content/plugins/ directory.
  2. Goto plugins menu and Activate Plugin
  3. Click the CSS & Javascript Toolbox link in the main navigation bar.

3. Scripts n Bearings

This plugin enables adding custom CSS and Javascript directly onto individual pages and posts. Your theme will need to have the relevant hook for it to work. It does not have any input validation. It comes with the following features:

  1. Ability to add classes to the body tag and post container.
  2. It provides a global setting page through which you can write scripts and styles for the entire blog.
  3. Ability to add classes to the TinyMCE ‘Formats’ dropdown, which can be used by the users to add styles to pages directly
  4. Ability to restrict unauthorized access.


This plugin does not require any unique activation. It can be downloaded from and installed like any other plugin.

As the name suggests, it moves all the texts to the footer. This helps to reduce loading time, clean up bottlenecks if there are too many scripts. However, it should be remembered that Scripts to footer runs there is a plugin, and wp_enqueue_scripts is being correctly used by the theme. Its main features are:

  1. Ability to disable specific features on specific pages.
  2. Ability to disable the plugin on specific archive pages such as blog pages, taxonomy page, search page, and more. It is done by disabling the plugin on those pages via a checkbox.
  3. Ability to choose scripts to be included in the header 


  1. Upload the scripts-to-footer.php to the /wp-content/plugins directory.
  2. Goto Plugins Menu > Activate the Plugin.

It helps to take advantage of the third-party APIs. Its free version comes with ads. Buying the pro version will remove ads and let will provide access to premium options. Its features include:

  1. Ability to add custom scripts into individual pages, header, or footer.
  2. Enables you to add Google remarketing code to the entire site 
  3. Support for WooCommerce
  4. Ability to add scripts to limited/selective pages or posts.
  5. Compatible with Gutenberg.
  6. Supports category and terms pages.


  1. Upload the plugin to the directory /wp-content/plugins/
  2. Activate the plugin through the ‘Plugins’ menu in Wordpress.
  3. Navigate to custom post type, post or page
  4. Paste code in the header or the footer.
  5. Save the post or the page.

6. Pure Custom CSS and JS

The pro version of the plugin is the most effective when used to its full potential. It mainly focuses on changes in the site appearance. Its main features are:

  1. Ability to add custom CSS and Javascript without modifying the plugin or the theme.
  2. Ability to change codes to specific URLs or page
  3. Test elements before making them live
  4. Text Editor with Syntax highlighting.
  5. Inline coding or maintain a separate code file.
  6. Ability to place code in the header or the footer
  7. Ability to add as much coding as required in the Admin or the Front-End
  8. Changes are saved even when they are changed.


Method 1
  1. Download the plugin from this link and save the .zip file
  2. Goto WP Admin Panel, click Plugins > Add New.
  3. Click Upload and browse to the .zip file that you have downloaded.
  4. Click ‘Install’ and ‘Activate Plugin’
Method 2
  1. Download the plugin from this link and save the .zip file
  2. Extract the .zip file 
  3. Access your website file directories via cPanel or FTP
  4. Go to wp-content/plugins directory
  5. Upload the extracted folder into this location.
  6. Goto WP Admin Panel, click Plugins > Add New.
  7. Goto WP Admin Panel > Plugins and click on Activate the Simple Custom CSS and JS plugin.
Method 3
  1. Goto WP Admin Panel, click Plugins > Add New.
  2. Type ‘Simple Custom CSS and JS’ in the browser input box
  3. Select the ‘Simple Custom CSS and JS’ plugin and click ‘Install.’
  4. Activate Plugin.


The are many other innumerable plugins that can be used depending upon the need of the hour. A Wordpress website finally ends up having many different plugins. All the themes and plugins must be loaded using standard Wordpress methods to ensure there are no incompatibility issues. A potential downside of Javascript is that it does not work if it is not enabled in the user’s browser. While modern-day browsers work well with Javascript, in case the user has turned off Javascript in his browser, then nothing will work. So, even after you add javascript codes that work well most of the time, it is wise to have a server-side fallback.

The Complete JavaScript Course 2024: From Zero to Expert!

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By Vijay Singh Khatri

With 5+ years of experience across various tech stacks such as C, C++, PHP, Python, SQL, Angular, and AWS, Vijay has a bachelor's degree in computer science and a specialty in SEO and helps a lot of ed-tech giants with their organic marketing. Also, he persists in gaining knowledge of content marketing and SEO tools. He has worked with various analytics tools for over eight years.

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