jQuery ajax setTimeout 0毫秒[重复]

Question

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            <div class="grid--cell mb0 mt8">Closed <span title="2012-08-23 06:31:08Z" class="relativetime">7 years ago</span>.</div>
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Possible Duplicate:
Why does setTimeout(fn, 0) sometimes help?

Reading jQuery 1.8 source,

WHY does it do setTimeout with 0 ms delay ? (instead of just executing the callback ?)

https://github.com/jquery/jquery/blob/1.8.0/src/ajax/xhr.js#L196

                if ( !s.async ) {                       
                    callback();
                } else if ( xhr.readyState === 4 ) {


                    // (IE6 & IE7) if it's in cache and has been
                    // retrieved directly we need to fire the callback

         //-------->// WHY do setTimeout with 0 ms delay ?
                    setTimeout( callback, 0 );
                } else {
                    handle = ++xhrId;

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Answer 1

The reason is that setTimeout adds the function to the browser event queue so it will only be invoked after the preceding events in the queue have been handled, allowing the rest of the function that sets the timeout to finish execution.