ui-check is a free Chrome add-on developed by 严文彬. It falls under the category of Browsers and specifically the subcategory of Add-ons & Tools. This add-on is designed to detect various limit states on web pages, including text overflow, missing images, and missing text.

In many cases, web pages appear to be in perfect condition during development, without considering factors such as excessive text or empty spaces, or ensuring proper image sizes. However, when these pages are actually deployed, they may encounter various boundary issues like text overflow, collapsed heights, or oversized images.

ui-check generates three extreme scenarios: "overflow", "blank", and "random". It also provides the option to restore the page to its "normal" state, making it convenient for developers and testers to compare and address various boundary situations.