Web Workers are a simple means for web content to run scripts in background threads. The worker thread can perform tasks without interfering with the user interface. In addition, they can make network requests using the fetch() or XMLHttpRequest APIs. Once created, a worker can send messages to the JavaScript code that created it by posting messages to an event handler specified by that code (and vice versa)....different constructor name (see index.html and index2.html ) — each...number that is a zero-based index position in the fibonacci sequence...