All those setTimeout answers here don't work!
I just want to wait a few seconds between two functions, like this:
do_fn1();
wait(5000);
do_fn2();
7 Answers
From phpied.com:
function sleep(milliseconds) {
var start = new Date().getTime();
for (var i = 0; i < 1e7; i++) {
if ((new Date().getTime() - start) > milliseconds){
break;
}
}
}
14 Comments
Andy E
-1 please don't use this or ever recommend it to anyone. JavaScript runs on the browser's UI thread, so any interaction with a web page will be impossible whilst "sleeping".
Gareth
The user won't be able to do anything during that sleep period (and no other script will be able to run). This is a poor answer
Felix Kling
@Frodo: If you do debugging, use proper debugging tools and set a break point!
devios1
+1 While I agree that spinning like this is pretty much never a good idea, I disagree with the downvotes to this answer because this is the answer to the question as posed. Using
setTimeout would be much better, but the OP specifically asked for a solution that doesn't use it. For very small and seldom delays (or, as the OP mentioned, debugging purposes), this solution could be acceptable.
Liangliang Zheng
First of all, +1 to leon's answer. Though I wouldn't ever use that solution in my code, it fit the question to some extent. I guess this would be a general topic. I think anyone spending time answering question should be treated with respect. A downvote is not necessary unless the answer is irrelevant, or bad + irrelevant. After all, we can always upvote the other better answer, or write a better one + comment on the other one.
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I don't think you can. You'll probably have to
do_fn1();
window.setTimeout(do_fn2, 5000);
3 Comments
Frodo
but I don't want to pass 2nd function as parameter. I have more functions following after it, and I want every one delayed..
Andreas Jansson
Just wrap them all in a new function.
Chris Baxter
@Frodo - Wrap all "delayed" functions in a wrapper function to pass in to the setTimeout.
Two thoughts:
first of all why not wrap up all of the post delay statements into a wrapper function
var postDelayFunc = function(){
dosomething();
dosomethingelse();
onemorething();
}
then in your code pass this function as the parameter to setTimeout.
//your code
dofunc1();
setTimeout(postDelayFunc, 1000);
Alternatively take a look at jQuery deferred: http://msdn.microsoft.com/en-us/scriptjunkie/gg723713, although you will probably end up writing very similar code.
One thing struck me though about your responses to other answers and possibly where the confusion arises. I think you are looking at your function and seeing a single thread you just want to hold up for a while before carrying on.
You should not do this though in javascript as it ties up the entire browser and will annoy the hell out of users. Instead what you are in effect doing when you use setTimeout, is indicating that when the timeout expires another thread will pick up and execute the passed in function.
As soon as the timeout has been set, the executing thread will continue with the next line (which is why you think the timeout isn't working). What you probably need to do, is set the timeout, and put ALL the post-execution steps into the function handed off to the timer as indicated above.
Comments
Saying they all don't work without an example is big call because I'm sure they probably do.
How about this,
do_fn1();
setTimeout(do_fn2, 5000);
Comments
All those setTimeout answers here don't work!
Of course they do:
function a() {
alert("I'm pretty sure...");
}
function b() {
alert("...that they work just fine.");
}
a();
setTimeout(b, 5000);
1 Comment
Frodo
I just realized, I could use alert instead of sleep
Another hack I will probably use, however personally I would not recommend it.
Check out here http://jsfiddle.net/S6Ks8/1/
function parseSleeps(func){
var fdef = func.toString();
var fbody = fdef.match(/\{([\s\S]*)\}/)[1].split(/sleep\(.*?\)\;?/);
var sleeps = fdef.match(/sleep\((.*?)\)/g);
var fargs = fdef.match(/\(([\s\S]*?)\)/)[1];
var fbodyNew = [];
var times = [];
fbodyNew.push(fbody.shift(), '\n');
for(var i = 0; sleeps && i < sleeps.length; i++){
var sec = sleeps[i].match(/\d+/)[0];
times.push(sec);
fbodyNew.push('setTimeout(function(){\n');
fbodyNew.push(fbody.shift(), '\n');
}
while(times.length){
var sec = times.pop();
fbodyNew.push('}, ', sec, ');\n');
}
return new Function(fargs, fbodyNew.join(''));
}
// Your code from here
function a(str1, str2){
alert(str1);
sleep(3000);
alert(str2);
}
var func = parseSleeps(a);
func('here', 'there');
Comments
The smartest way would be to have something like
function a() {
// Do stuff
setTimeout(b, 42)
}
function b() {
// Do other stuff delayed
}
Never "block" any Threads in JS - if you think you have to do there is definately a "cleaner" way to do achieve your aim.
Comments
setTimeoutdoesn't work whilst posting an example thatsetTimeoutwould be absolutely perfect for seems somewhat counter productive (hence all the answers just telling you to use it). Perhaps you should improve your question to show exactly what you need to do and why you can't do it withsetTimeout?setTimeout. The OP wants to pause execution for a period of time without relinquishing execution back to the DOM, like howsetTimeoutdoes.