JavaScript reads a page twice: as the server sends it, and after a browser has run the page's scripts. The big number is the share of the page's text that only appears after the scripts run.
| Status | What it means |
|---|---|
| Passed | Under 10% of the text needs JavaScript. |
| Warning | 10% to under 50% of the text needs JavaScript. |
| Error | 50% or more needs JavaScript, or the page is an empty shell that scripts fill. |
Press Details to see what changes after JavaScript (text, links, title, meta description, canonical link, structured data and any redirect), which AI crawlers are reported to run JavaScript, and what to fix.
How it is worked out
The first read is the page as a crawler that does not run scripts gets it. The second runs in a real browser. The words that appear only in the second read are counted and divided by all the words in it. This is a risk, not proof: a crawler that runs JavaScript sees the page as the browser did.
Which crawlers run JavaScript is taken from outside measurements, with the date shown. The crawler companies rarely say, so treat the list as a guide.
Where to find it
Site check shows the homepage. On Pages, choose a page, then use Check in the Bot view card. The browser read uses limited browser time, so the Bot view button reads one page at a time.
What to do next
If the text only appears after JavaScript, ask your developer for server-side rendering or prerendering, so the text is in the page's HTML when it is first sent. If only structured data or links are added later, move them into the page's HTML or theme.