Window.setImmediate()
Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
This method is used to break up long running operations and run a callback function immediately after the browser has completed other operations such as events and display updates.
Syntax
var immediateID = setImmediate(func, [param1, param2, ...]);
var immediateID = setImmediate(func);
-
where
immediateID
is the ID of the immediate which can be used later withwindow.clearImmediate
. func
is the function you wish to call.
All parameters will be passed directly to your function.
Notes
The clearImmediate
method can be used to clear
the immediate actions, just like clearTimeout
for
setTimeout()
.
This method can be used instead of the setTimeout(fn, 0)
method to execute
heavy
operations.
The feature can be emulated in a few different ways:
-
postMessage
can be used to trigger an immediate but yielding callback. Do note that Internet Explorer 8 includes a synchronous version ofpostMessage
, which means it cannot be used as a fallback. -
MessageChannel
can be used reliably inside of Web Workers whereas the semantics of postMessage mean it cannot be used there. -
setTimeout(fn, 0)
can potentially be used, however as it is clamped to 4ms for timers nested more than 5 levels deep per the HTML spec, it does not make for a suitable polyfill for the natural immediacy ofsetImmediate
.
All of these techniques are incorporated into a robust setImmediate polyfill.
Specifications
Not part of any current specifications. The Efficient Script Yielding specification is no longer being worked on.
Browser compatibility
BCD tables only load in the browser