Web Alert is an Android app developed by Cristian Florin Slav that allows you to set alerts for product prices, news, exam results, concert dates, and more. The app lets you track sections of a webpage with a built-in selector similar to jQuery or CSS selector. You can interpret the selection in three ways: as text, number, or date. Additionally, you can use regular expressions in a search and replace to extract useful information from the selected elements. Web Alert offers tutorials on how to use the app for text, number, and date alerts. For a full documentation of the selector syntax and date and time patterns, you can visit the developer's website.