JavaScript can make your website dynamic, but too much unused JS can slow it down, hurt SEO, and frustrate users.
Want a faster, high-performing website? Learn how to find and remove unused JavaScript with these easy techniques!
🔍 How to Use Chrome DevTools Coverage Tab to Detect Unused JavaScript
Chrome DevTools has a powerful feature to analyze code usage—the Coverage Tab. Here’s how you can use it:
Open Chrome DevTools: Press F12 or Ctrl + Shift + I (Windows/Linux) or Cmd + Option + I (Mac).
Go to the Coverage Tab: Click on the three-dot menu in DevTools → "More tools" → "Coverage."
Start Recording: Reload the page and observe the coverage results.
Analyze the Results: You’ll see a list of JavaScript and CSS files, along with used (%) and unused code.
Remove Unused Code: Identify scripts that are loading but not being used, then remove or optimize them.
💡 Pro Tip: Check out Google's official guide on optimizing JavaScript for more details!
⚠️ Removing Third-Party Scripts Safely
Many websites load third-party scripts (e.g., analytics, chat widgets, ads) that slow down performance. Removing them recklessly can break functionality. Here’s how to do it safely:
✅ Audit Third-Party Scripts: List all external scripts (Google Tag Manager can help).
✅ Check Usage: Use DevTools or tools like RequestMap to see script dependencies.
✅ Lazy Load Scripts: Only load scripts when needed using the defer or async attributes.
✅ Self-Host Where Possible: Instead of loading scripts from third-party sources, download and serve them from your own server.
🔗 Resource: Learn how to defer JavaScript for better performance: web.dev/defer-non-essential-js
🛠️ Best Tools for Detecting and Removing Unused Code
Several tools help automate the process of finding and removing unused JS. Try these:
PurifyCSS: Helps eliminate unused CSS & JS (purifycss.online)
Webpack Tree Shaking: Optimizes your JavaScript bundle by removing dead code (Webpack Docs)
UnCSS: Scans your HTML & removes unnecessary CSS/JS (uncss GitHub)
Lighthouse: Google’s performance tool that flags unused JavaScript (Run Lighthouse)
🔹 Bonus: Learn how Webpack tree shaking works with this hands-on guide: webpack.js.org/guides/tree-shaking
🚀 Make Your Website Faster Today!
Unused JavaScript is slowing down your website and affecting SEO! By following these steps, you’ll:
✅ Improve page load speed
✅ Boost Core Web Vitals
✅ Enhance user experience
✅ Rank higher in search results
🔹 Have you tried removing unused JavaScript? Share your experience in the comments! Let’s discuss the best strategies to improve website performance.
🔗 Need help optimizing your website? DCT Technology Pvt Ltd can assist with performance audits and IT consulting!
📢 Tag a developer who needs to see this! Let’s build faster, better websites together. 🚀
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