How can I reduce JavaScript execution time to improve site performance?

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How can I reduce JavaScript execution time to improve site performance?

Asked on Jan 10, 2026

Answer

Reducing JavaScript execution time is crucial for improving site performance, as it directly impacts metrics like First Input Delay (FID) and Total Blocking Time (TBT). By optimizing the way JavaScript is loaded and executed, you can enhance user experience and overall site speed.

<!-- BEGIN COPY / PASTE -->
    <script src="example.js" async></script>
    <script src="another-example.js" defer></script>
    <!-- END COPY / PASTE -->

Additional Comment:

Use the "async" attribute to load scripts asynchronously, allowing other page elements to load without delay.
Apply the "defer" attribute for scripts that can wait until the HTML document is fully parsed.
Minify and bundle JavaScript files to reduce file size and the number of HTTP requests.
Consider code-splitting to load only necessary JavaScript for the initial page view.
Evaluate and remove any unused JavaScript to decrease execution time.

✅ Answered with Core Web Vitals best practices.

Ask any question about Performance here... and get an instant response.

How can I reduce JavaScript execution time to improve site performance?

Asked on Jan 10, 2026

Answer

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