UserScripts are small pieces of JavaScript code that allow users to customize the way web pages look and function. They can modify content, automate tasks, or enhance user experience on websites. Users typically install these scripts through browser extensions like Tampermonkey or Greasemonkey. These scripts are often shared within communities, enabling users to benefit from each other's creations. By using UserScripts, individuals can tailor their browsing experience to better suit their needs, making the web more efficient and enjoyable.