Render probe

This page is a research instrument, not an article. It records which crawlers run JavaScript on jsseo.dev. The plan and the decision rule are pre-registered in the project repository.

Three sentences

Sentence one is plain HTML. Its phrase is amber otter.

Sentence two appears only if the inline script runs.

Sentence three appears only if the external script runs.

How it works

The second and third sentences are written by JavaScript: one by a script inside this page, one by a separate file. Each script also sends a request to a URL that exists only while it runs. A crawler that reads the HTML sees the first sentence. A crawler that runs the scripts sees all three, and its requests show up in our logs.

Background: GPTBot downloads your JavaScript. It does not run it, and the test bed.