Is this browser-dependent javascript code?

Question

Why different output in IE and FF?
In IE its showing : Hello and In FF its showing : Hi

var message = "Hi";
setTimeout(function(){alert(message);},10);
setTimeout(function(){message = "Hello";},0);

what is standarad? which browser is doing it right?

Note: if i convert 10 to 11 in FF then it shows Hello

Answer 1

Firefox handles small delays differently to IE. Firefox have a min delay time of 10ms (which isn't exact either). See the notes of https://developer.mozilla.org/en/window.setTimeout for more info.

Answer 2

On my PC I ran it in both FF and IE, and I had exactly the opposite results.

The reason for this is your timeout is just 10 milliseconds long. The resolution of Timers on Windows is actually about 10ms, so it's possible that either timeout could happen first. To be really sure that one thing happens before the other, you should definitely have a wider gap between timeouts.

And even then, you shouldn't expect it to always work :-)

If you really want to do things in the same order, keep it in the same line of code, or set flags saying whether or not a particular action has been completed, and check that before doing a second one which relies on the first.