How to Minimize Unused JavaScript and Speed Up Blogger

Reducing unused JavaScript in Blogger is an important step for improving your website’s performance, loading speed, and SEO. By eliminating unnecessary code and optimizing the way JavaScript is loaded, you can reduce the page load time and improve the user experience. Here’s how to do it:

1. Identify Unused JavaScript

Before you can reduce unused JavaScript, you need to know which scripts are being loaded but not used.

• Google Chrome DevTools:
  Use Google Chrome’s Developer Tools to identify unused JavaScript:

  1. Open your Blogger site in Chrome.
  2. Right-click and select Inspect or press Ctrl + Shift + I.
  3. Go to the Network tab and refresh the page.
  4. In the Coverage tab, you'll see a breakdown of which JavaScript files are being loaded and how much of them is used. This will help you spot unused code.

• Lighthouse:
  Run Lighthouse from Chrome DevTools (under the Audits tab) to generate a performance report, which can highlight unused JavaScript files.

2. Remove Unnecessary JavaScript Files

After identifying unused JavaScript, you can remove or modify the code:

• Delete Unused Scripts:
  Review the HTML template in Blogger (under Theme > Edit HTML) to remove any JavaScript files that are not necessary for your site.

  • For example, if a particular widget or plugin is not being used, remove its script tags.

• Disable Third-Party Scripts:
  If you have third-party scripts or widgets (e.g., social sharing buttons, analytics scripts) that you don’t use, remove them from your template.

• Example: Remove unused ad scripts, tracking pixels, or analytics trackers that aren't essential.

3. Load JavaScript Asynchronously or Defer It

One way to optimize the loading of JavaScript is to delay its execution until after the page has loaded:

• Defer JavaScript Loading:
  Adding the defer attribute to the <script> tags ensures that JavaScript is executed after the page content is loaded. This improves the page’s First Contentful Paint (FCP) and overall load speed.

  <script src="path-to-your-script.js" defer></script>
  

• Async JavaScript:
  If a script does not depend on others, you can use the async attribute. This allows the script to load in parallel with other resources without blocking the page rendering.

  <script src="path-to-your-script.js" async></script>

4. Combine and Minify JavaScript Files

Reducing the number of requests made to load JavaScript files can significantly improve page load speed. You can combine multiple JavaScript files into a single file and minify them to reduce their size.

• Combine JavaScript Files:
  Combine several JavaScript files into one. This will reduce the number of HTTP requests, which can boost performance.

• Minify JavaScript:
  Minify your JavaScript files to remove unnecessary spaces, comments, and line breaks. There are several online tools available to help with this, such as:

• Terser
• UglifyJS
• Minifier

5. Use Lazy Loading for Non-Critical JavaScript

Lazy loading allows you to load JavaScript only when it is needed. This is particularly useful for widgets or scripts that are not immediately required, such as third-party widgets or ad scripts.

• You can implement lazy loading by adding an event listener that waits until the user interacts with certain elements or scrolls to a certain part of the page before loading the scripts.
• Example for loading scripts when scrolled into view:

  window.addEventListener('scroll', function() {
    if (window.scrollY > 500) {
      // Load your JavaScript file after scrolling down
      var script = document.createElement('script');
      script.src = 'path-to-lazy-script.js';
      document.head.appendChild(script);
    }
  });

6. Use a Content Delivery Network (CDN)

Using a CDN can help serve your JavaScript files from servers closer to the user's location, speeding up load times. Many popular JavaScript libraries (like jQuery) are already hosted on CDNs, so you can link to them instead of hosting them yourself.

• Example:

  <script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>

7. Implement Code Splitting

If your site uses a lot of JavaScript, consider code splitting, which is a technique that breaks the JavaScript into smaller, more manageable chunks. You can load only the JavaScript needed for each page, reducing unused JavaScript on each page.

• Code splitting can be challenging to implement directly on Blogger, but you can use tools like Webpack or Parcel to bundle and optimize your JavaScript files if you host your own scripts.

8. Use Built-in Blogger Optimization Features

Blogger provides basic performance optimization features:

• Go to Blogger Dashboard > Theme > Customize > Advanced and enable any performance-related settings such as lazy load images or custom HTML widgets.

Conclusion

Reducing unused JavaScript on Blogger requires a combination of careful monitoring, optimization, and the removal of unnecessary scripts. By following these steps, you can significantly improve your site’s performance, which will benefit both your users and SEO rankings.