JS Execution Time Test
What is it?
This test will check the total execution time of the JavaScript code. Reducing the JavaScript execution time, in general, refers to decreasing the amount of time spent to parse, compile and execute the JavaScript code. Improving JavaScript execution time will result in faster page load times, and improved user experience (which Google uses as a factor in its ranking algorithms).
Pass rate:
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Top 100 websites: 53%This value indicates the percent of top 100 most visited websites in the US that pass this test (in the past 12 months).
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All websites: 88%This value indicates the percent of all websites analyzed in SEO Site Checkup (500,000+) in the past 12 months.
| 2021 | 79% |
|---|---|
| 2022 | 78% |
| 2023 | 71% |
| 2024 | 53% |
100
75
50
25
0
How do I fix it?
In order to pass this test you have to decrease the JavaScript code execution time. You can do this by:
- implementing code-splitting: split the JavaScript bundle into smaller files so that only the critical code is executed during initial page load.
- removing unused code: unused code can often be inherited from previous versions of your site, and/or imported from other modules that aren't referenced anymore.
- reduce network trips by caching your code with the PRPL pattern: preload the most important resources, render the initial route as soon as possible, pre-cache remaining assets and lazy load other routes and non-critical assets.
- minifying and compressing the JavaScript code
