A programming interface (API) from the Web Hypertext Application Technology Working Group (WHATWG) that enables Web-based programs to launch scripts that run in the background while the user interacts with the software on screen.
For example, a highly computational task can be running in the background without causing interruptions to the user interface. With background "workers" scripts, Web Workers was designed to invoke one or two reasonably intensive background processes, not numerous minor ones. See
AJAX.