how to coordinate 2 functions with timers -> javascript

I am constructing a little app in javascript right now but I've clashed into a serious problem.

I am using at least 3 functions with timers on them (the 1st two running endlessly) and both of them use some global variables (in this case they are needed to be globa开发者_开发问答l because of some functions). The external functions external to those 3 don't have timers. One of the timer functions only activates when a certain action is taken, affecting the second function (right now I disabled it qith a flag). Still, when this timer function ends the other one is still running, trying to get some incoherent data (trying to get to negative indexes on a matrix to be precise) and crashing (the flag is switched but the main data isn't fixed yet -> like a multi-threading problem).

What I want to ask is, there is any way to make a function "wait" for another to end in javascript? Or any other way or coordinating those functions between them (in mutex style or sort of)?

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Javascript is single threaded, so it's going to be nearly impossible to come up with any sort of "multi-threading" type solution. I would try to come up with some way to use a single function and one timer, and handle the different pieces of logic with flags. For example, maybe you could do one piece of the logic if flag A is set, then set flag B. When the timer fires again, you could do the flag B logic (using this same function).

On a more positive note, it does seems that HTML5 will support multithreading, which is encouraging, but it doesn't really address the problem at hand.

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Javascript is actually single threaded, except that timers execute asynchronously.

If this is running in a browser then I strongly recommend using jQuery's new "deferred" objects, or any other framework that implements something similar.

These allow you to trigger another callback only when all of a set of asynchronous events have completed, which may be just what you need.