I\'m working with a code that handles all AJAX requests using Web Workers (when available). These workers do almost nothing more than XMLHttpRequest
object hand
You are optimizing your code in the wrong place.
AJAX requests already run in a separate thread and return to the main event loop once they fulfil (and call the defined callback function).
Web workers are an interface to threads, meant for computationally expensive operations. Just like in classical desktop applications when you don't want to block the interface with computations that take a long time.