Unexecuted code
The size of each JavaScript file and the share of code that did not run during page load.
Website JavaScript analysis
Find which scripts load, which code runs and which JavaScript errors appear. The scan observes one page load without clicks or scrolling. Use the findings to choose what to investigate next.
What the scan shows
The scanner checks one page load in Chromium, without clicks or scrolling.
Main thread activity
Script execution time, long tasks, and memory usage during page load.
Script loading
File and transfer sizes, HTTP statuses, load times, and loading methods: async, defer, module, or dynamic import.
Third-party scripts
Scripts with a different hostname, with their URLs, sizes, and loading methods.
JavaScript errors
Console messages, unhandled exceptions, and browser warnings about deprecated APIs.
Bundle contents
Source modules can be mapped when a valid source map is available and readable. Missing or unsupported maps leave this part incomplete; the resource and error checks still work.
How to read the results
Can I delete unexecuted code?
Not from one load alone. For example, app.js may contain a checkout function that does not run on the landing page. Locate the resource, test the checkout and other states, then consider splitting or deferring it. Unexecuted code is not automatically safe to delete.
How is a third-party script identified?
The scanner compares the script hostname with the page hostname. Subdomains and your own CDN are also included in this group. This alone does not indicate a problem.
Are source maps required?
The main resource and error report works without them. To inspect source modules inside a bundle, the scanner needs a supported, valid map that it can read. A missing module map is not evidence that the bundle contains no unused code.
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Open