For users on slow connections, such as 2G, 3G, or slow Wi-Fi, external
scripts dynamically injected via
document.write() can delay the display of
main page content by tens of seconds.
See Intervening against
document.write() to learn more.
In your report, Lighthouse lists out every call to
Review this list, and note any call that dynamically injects a script.
If the script meets the criteria outlined in the introduction to
document.write(), Chrome won't execute the
injected script. These are the calls to
document.write() that you want
to change. See How do I fix this? for possible solutions.
Lighthouse reports every instance of
document.write() that it encounters.
Note that Chrome's intervention against
document.write() only applies to
render-blocking, dynamically-injected scripts. Other uses of
may be acceptable.
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