Develop Reference

How do I delay this code running in JavaScript?

I have written this code to change an image:
change = function(){
for (r=0; r<6; r++){
for (i = 0; i < 6 ; i++) {
setInterval(imgfile(number=i+1), 5000);
}
}
}
imgfile= function(number){
a = 'document.getElementById("imgdiv").src = "images/'+number+'.svg"';
eval(a);
}
The function change() is called when a button is clicked.
When I press the button the image changes straight to 6.svg, when I want it to go through the images 1, 2, 3, 4, 5, 6 and to repeat it 6 times. When I change setInterval to change.setInterval or imgfile.setInterval it doesn't work at all. How do I fix this?

change = function(i=0){
imgfile(i%6+1);//change image
if(i<36) setTimeout(change,5000,i+1);//next image in 5 seconds
}
imgfile= function(number){
document.getElementById("imgdiv").src = "images/"+number+".svg";//no need to use ev(i||a)l
}
Instead of loop/interval mess you can simply start a timeout that restarts itself after changing the image... This code will loop over 6 images with a delay of 5 seconds and that 6 times...

Something like this, perhaps?
var index, imgCount, loopCount, imgTag, countdown;
index = 0;
imgCount = 6;
loopCount = 6;
imgTag = document.getElementById('imgdiv');
countdown = function () {
if (index < imgCount * loopCount) {
imgTag.src = 'images/' + index % imgCount + '.svg';
index = index + 1;
setTimeout(countdown, 5000);
}
};
countdown();
Here we're avoiding the double loop and using modular math (index % imgCount) to get the right file number.

For another question I wrote a nice utility function that has quite a number of uses, but can also handle this scenario very easily. The main issue is that there is no time elapsing between the different delays being set. So you are setting 6 different actions to all happen within 5000ms, and all will occur at the same moment.
Here's my original answer
Here's the utility function for that answer, along with its application to your problem.
function doHeavyTask(params) {
var totalMillisAllotted = params.totalMillisAllotted;
var totalTasks = params.totalTasks;
var tasksPerTick = params.tasksPerTick;
var tasksCompleted = 0;
var totalTicks = Math.ceil(totalTasks / tasksPerTick);
var initialDelay = params.initialDelay;
var interval = null;
if (totalTicks === 0) return;
var doTick = function() {
var totalByEndOfTick = Math.min(tasksCompleted + tasksPerTick, totalTasks);
do {
params.task(tasksCompleted++);
} while(tasksCompleted < totalByEndOfTick);
if (tasksCompleted >= totalTasks) clearInterval(interval);
};
// Tick once immediately, and then as many times as needed using setInterval
if (!initialDelay) doTick();
if (tasksCompleted < totalTicks) interval = setInterval(doTick, totalMillisAllotted / totalTicks);
}
// Do 6 actions over the course of 5000 x 6 milliseconds
doHeavyTask({
totalMillisAllotted: 5000 * 6,
totalTasks: 6,
tasksPerTick: 1,
initialDelay: false, // Controls if the 1st tick should occur immediately
task: function(n) { console.log('Set image to "images/' + (n + 1) + '.svg"'); }
});

You want to do setTimeout().
setTimeout pauses for the millesecond value and then does the code. Where setInterval runs the code every whatever milleseconds.
Yeah, don't do change.setInterval or whatever, it is just setInterval.
An example for you would be this inside the for loop to replace the setInterval function.
setTimeout(imgfile(i+1), 5000);

Javascript setInterval for sequential numbers

I'm writing some code that looks like this
<script type="text/javascript">
setInterval(function write_numbers(){
var count = 1;
var brk = "<br>"
while (count < 1218){
document.write(count + brk);
count++;
}},1000)
</script>
I need it to display the first number which is one then wait one second then display the next number (2) then wait a second, I need this to carry on till it reaches 1218 then stop.
With the code I've written it just writes all the numbers up, waits a second then repeats all the numbers again.
I'm quite new to coding so i don't know how to fix this.
If someone could tell me how to do it, it would be greatly appreciated.

There are multiple issues in your code, although you are using setInterval(), since you have a while loop inside it, the complete loop will be executed every 1 second.
Instead you need to have the setInterval() callback use an if statement to check whether to print the value or not like
var count = 1;
var interval = setInterval(function write_numbers() {
if (count <= 1218) {
document.body.appendChild(document.createTextNode(count));
document.body.appendChild(document.createElement('br'));
count++;
} else {
clearInterval(interval);
}
}, 1000)

The below script should do the trick for you:
<script>
var count = 1;
var brk = "<br>";
var myVar = setInterval(function(){ myTimer() }, 1000); // This should be a global variable for clearInterval to access it.
function myTimer() {
document.write(count + brk);
count++;
if(count > 1218){
myStopFunction();
}
}
function myStopFunction() {
clearInterval(myVar);
}
</script>

two issues
1) If you are using setInterval then you must clear the interval as well otherwise it will be an infinite loop
2) use if rather than while so that number is printed one by one.
try this
var count = 1;
var interval1= setInterval(function write_numbers(){
var brk = "<br>"
if (count < 1218)
{
document.write(count + brk);
count++;
}
else
{
count = 1;
clearInterval(interval1);
}
},1000);

First, you should define count outside setInterval. Defining inside will reset it every time.
Second, while (count < 1218){} should be a conditional statement. I have considered if(count>= 1218) as termination condition.
Third, when even you use setInterval, remember to use clearInterval as well.
Code
var count = 1;
var interval = setInterval(function write_numbers() {
var brk = "<br>"
document.write(count + brk);
count++;
if (count >= 10) {
window.clearInterval(interval);
}
}, 1000)

Try this code man , only one change from your code.
count variable declare out side of the setInterval function
<script type="text/javascript">
var count = 1;
setInterval(function write_numbers(){
var brk = "<br>"
if (count < 1218)
{
document.write(count + brk);
count++;
}
},1000);
</script>

For Loop Delay Without setTimeout

So, here's my problem... I've got a for loop inside a function
var fan1 = function () {
for(var i=0; i<flare1base.length; i++) {
for(var i=0; i<200; i++)
flare1base.rotation.z += 0.01;
};
};
It should do essentially that, fairly simple, but... I need it to wait 10 milliseconds before adding to the rotation again. The problem is I don't think I can use setTimeout or just use setInterval instead of the entire for loop, because it's acting on an object in an array, and if I do
f1 = setInterval("flare1array[i].rotation.z += 0.01",10);
setTimeout("clearInterval(f1)",2000);
It queues up an action to do rotate the thingy, but by the time the action occurs the for loop has gone around again and "i" is different.

See jQuery: Wait/Delay 1 second without executing code
Have you tried:
setTimeout(function (){
flare1array[i].rotation.z += 0.01;
}, 10);

How about using setInterval and then clearInterval? You could do something like this:
function rotate(max) {
var i = 0;
return function () {
flare1base.rotation.z += 0.01;
if (++i == max) clearInterval(id);
}
}
var id = setInterval(rotate(200), 10);
Similar example on JSFiddle
setInterval returns an id that can later be passed to clearInterval to prevent the action from continuing indefinitely. Here I've wrapped a counter variable i in a closure, which keeps track of how many times the inner function has been called. When it has been called max times, it stops.
By the way, if you know what the starting value of flare1base.rotation.z is, it would be better to calculate it afresh each time the function is called rather than continuously adding 0.01, as the result of repeated floating point additions may be imprecise. For example, if you know it starts at, you could do flare1base.rotation.z = 0.01 * ++i; (and remove the increment from the if statement).
To extend this to an array of items, you can wrap the whole process in a loop. Assuming that your items are in an array arr:
function rotate(arr, idx, max) {
var i = 0;
return function () {
arr[idx] += 0.01;
if (++i == max) clearInterval(ids[idx]);
}
}
var ids = new Array(5);
for (var i = 0; i < 5; ++i) {
ids[i] = setInterval(rotate(arr, i, 200), 10);
}
updated JSFiddle

Delay javascript code execution inside for loop

I have the following for loop:
for (var i = tileLog.length - 1; i >= 0; i--) {
$('.' + tileLog[i]).mouseenter();
};
1 < tileLog.legth < 1025
Is there a way to delay each iteration of the loop so that mouseenter() is triggered every x miliseconds?
I have tried:
function doSetTimeout(i) {
setTimeout(function() { $('.' + i).mouseenter(); }, 250);
}
for (var i = tileLog.length - 1; i >= 0; i--)
doSetTimeout(tileLog[i]);
This doesn't seem to work, it just delays by 250ms then iterates through the loop

As an alternative to using setTimeout() you could also use setInterval().
Define a running variable in the outer scope (like your running i in the loop).
In each iteration, besides calling your function, decrement the running variable. If it is below zero, stop the setInterval()`` :
var index = tileLog.length - 1,
timer = setInterval( function(){
$('.' + tileLog[index]).mouseenter();
index -= 1;
if ( index < 0 ) {
clearInterval( timer );
}
}, 250 );
There is no actual sleep() function or something similar. Would also be problematic as JavaScript (for most cases) is single threaded and such a method would block the render thread, thus rendering your browser inaccessible.

There is no sleep or such in JavaScript. So your approach with timeout is correct.
var tileLog;
var i = titleLog.length - 1;
function func1() {
$('.' + tileLog[i]).mouseenter();
if (--i) {
window.setTimeout(func1, 250);
}
}
// and of course start the process
func1();

How to create pause or delay in FOR loop?

I am working on a website, where I need to create a pause or delay.
So please tell me How to create pause or delay in for loop in javascript or jQuery
This is a test example
var s = document.getElementById("div1");
for (i = 0; i < 10; i++) {
s.innerHTML = s.innerHTML + i.toString();
//create a pause of 2 seconds.
}

You can't use a delay in the function, because then the change that you do to the element would not show up until you exit the function.
Use the setTimeout to run pieces of code at a later time:
var s = document.getElementById("div1");
for (i = 0; i < 10; i++) {
// create a closure to preserve the value of "i"
(function(i){
window.setTimeout(function(){
s.innerHTML = s.innerHTML + i.toString();
}, i * 2000);
}(i));
}

var wonderfulFunction = function(i) {
var s = document.getElementById("div1"); //you could pass this element as a parameter as well
i = i || 0;
if(i < 10) {
s.innerHTML = s.innerHTML + i.toString();
i++;
//create a pause of 2 seconds.
setTimeout(function() { wonderfulFunction(i) }, 2000);
}
}
//first call
wonderfulFunction(); //or wonderfulFunction(0);
You can't pause javascript code, the whole language is made to work with events, the solution I provided let's you execute the function with some delay, but the execution never stops.

I tried all one, but I think this code is better one, it is very simple code.
var s = document.getElementById("div1");
var i = 0;
setInterval(function () {s.innerHTML = s.innerHTML + i.toString(); i++;}, 2000);

if you want to create pause or delay in FOR loop,the only real method is
while (true) {
if( new Date()-startTime >= 2000) {
break;
}
}
the startTime is the time before you run the while
but this method will cause the browsers become very slow

It is impossible to directly pause a Javascript function within a for loop then later resume at that point.

This is how you should do it
var i = 0;
setTimeout(function() {
s.innerHTML = s.innerHTML + i.toString();
i++;
},2000);

The following code is an example of pseudo-multithreading that you can do in JS, it's roughly an example of how you can delay each iteration of a loop:
var counter = 0;
// A single iteration of your loop
// log the current value of counter as an example
// then wait before doing the next iteration
function printCounter() {
console.log(counter);
counter++;
if (counter < 10)
setTimeout(printCounter, 1000);
}
// Start the loop
printCounter();

While several of the other answers would work, I find the code to be less elegant. The Frame.js library was designed to solve this problem exactly. Using Frame you could do it like this:
var s = document.getElementById("div1");
for (i = 0; i < 10; i++) {
Frame(2000, function(callback){ // each iteration would pause by 2 secs
s.innerHTML = s.innerHTML + i.toString();
callback();
});
}
Frame.start();
In this case, it is nearly the same as the examples that use setTimeout, but Frame offers a lot of advantages, especially if the you are trying to do multiple or nested timeouts, or have a larger JS application that the timeouts need to work within.

I am executing a function where I need access to the outside object properties. So, the closure in Guffa solution doesn't work for me. I found a variation of nicosantangelo solution by simply wrapping the setTimeout in an if statement so it doesn't run forever.
var i = 0;
function test(){
rootObj.arrayOfObj[i].someFunction();
i++;
if( i < rootObj.arrayOfObj.length ){
setTimeout(test, 50 ); //50ms delay
}
}
test();

The way I found was to simply use setInterval() to loop instead. Here's my code example :
var i = 0;
var inte = setInterval(() => {
doSomething();
if (i == 9) clearInterval(inte);
i++;
}, 1000);
function doSomething() {
console.log(i);
};
This loops from 0 to 9 waiting 1 second in between each iteration.
Output :
0 1 2 3 4 5 6 7 8 9

It is not possible to pause a loop. However you can delay the execution of code fragments with the setTimeout() function. It would not make a lot of sense to pause the entire execution anyway.

I am using while loop and check the pause variable to check the user pause/resume the code.
var pause = false;
(async () => {
for (let index = 0; index < 1000; index++) {
while (pause) {
await new Promise((res) => setTimeout(res, 1000));
console.log("waiting");
}
await new Promise((res) => setTimeout(res, 1000));
console.log(index);
}
})();
const pausefunc = async () => {
pause = true;
};
const playfunc = () => {
pause = false;
};
<button onclick="playfunc()">Play</button>
<button onclick="pausefunc()">Pause</button>

I used a do...while loop to put a delay in my code for a modal dialog that was closing too quickly.
your stuff....
var tNow = Date.now();
var dateDiff = 0;
do {
dateDiff = Date.now() - tNow;
} while (dateDiff < 1000); //milliseconds - 2000 = 2 seconds
your stuff....