LH JavaScript Error Log records the JavaScript errors visitors hit on every site in a network, including scripts, stylesheets and images that fail to load, so problems that only show up in someone else’s browser can be found and fixed.
Each distinct error is stored once, with a count of how often it has happened and details of its latest occurrence, so a noisy page shows what is actually wrong rather than thousands of repeats. Errors raised by browser extensions are ignored. Network administrators browse the log under the LH Network Tools menu, and AI agents can list errors, read one in full and get summary statistics through MCP abilities.
Requires LH Beacon, which delivers the reports when a page is hidden or closed. Network-activate both; the log and its abilities live on the main site.