Develop Reference

For-loop not working till the specified input

The loop in myFunctionlp, is not working to the specified user input through prompt which is round in this case. I want that loop to run until the input of the user which I am getting through prompt. myFunctionlp is being called by a button press.
var round = prompt("Enter number of rounds");
var defaultNumberOfRounds = 1;
var roundno = isNaN(Number(round)) ? defaultNumberOfRounds : round;
var images_arr = ["../img/paper.png", "../img/stone.png",
"../img/sisor.png"
];
var size = images_arr.length;
console.log(`round: ${round}, roundno: ${roundno}`);
function myFunctionlp() {
for (var i = 0; i < roundno; i++) { //this loop
console.log(i);
setInterval(function() {
var x = Math.floor(size * Math.random())
$('#random').attr('src', images_arr[x]); // JQuery
}, 1500);
setInterval(function() {
var sound = new Audio("../audio/audio.mp3");
sound.play();
if (s == 50) {
sound.pause();
} else {
alert("Hello");
}
}, 3000);
}
}
function stop() {
for (s = 0; s < 51; s++) {
console.log(s);
}
}
function extra() {
var music = new Audio("../audio/audio_3.mp3");
music.play();
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<button class="onClick" onclick="myFunctionlp()">Play</button>

clearInterval and set it again after x seconds

I want to do simple interval with with if, It is checking a variable's value and doing a function again().
again function contains clearInterval, i++ and setTimeout to call interval again after x seconds
var speed = 1000;
var wait = 0;
var i = 0;
function init() {
setInterval(function() {
if (i >= 6) i = 0;
if (i == 4) {
wait = 5000;
again(wait);
} else {
document.body.innerHTML = i;
i++;
}
}, speed);
}
function again(time) {
clearInterval(init());
i++;
setTimeout(function() {
setInterval(init(), speed);
}, time);
}
init();
I expect output like this:
1, 2, 3, Waiting x sec's , 5, 1, 2, ...
but code is doing some thing crazy, Its going faster and faster. I don't know why.
Here's a codepen with example (can crash your browser!)
Can you fix it and explain? Thanks

You are not clearing interval but use function inside clearInterval method. Method init which is used has no return statement so clearInterval gets undefined in attribute, so it is not clearing nothing.
Fixed code:
var speed = 1000;
var wait = 0;
var i = 0;
var interval=null;
function init() {
interval = setInterval(function() {
if (i >= 6) i = 0;
if (i == 4) {
wait = 5000;
again(wait);
} else {
document.body.innerHTML = i;
i++;
}
}, speed);
}
function again(time) {
clearInterval(interval);
i++;
setTimeout(function() {
init()
}, time);
}
init();
Function setInterval returns interval id and function clearInterval in attribute should get id of interval which we want to stop, so I created interval variable to save id. I am using this variable in clearInterval.

This is a small example how changing the delay of a setInterval call.
(function iife() {
var timer = null,
counter = 0;
function task() {
counter += 1;
console.log(counter);
// condition: every four reps
if (counter % 4 === 0) {
console.log("changed speed to 4 seconds");
return start(4000);
}
// condition: every seven reps
if (counter % 7 === 0) {
console.log("changed speed to 2 seconds");
return start(2000);
}
}
function start(delay) {
clearInterval(timer);
console.log("runs every " + delay + " miliseconds");
timer = setInterval(task, delay);
}
start(1000);
}());

Resume a function after clearInterval

I have this code:
jQuery(function($) { // DOM is ready
var $el = $("header tr"),
tot = $el.length,
c = 0;
var timer = setInterval(function() {
$el.removeClass("current").eq(++c % tot).addClass("current");
}, 3000);
$el.first().addClass("current");
$el.on({
mouseenter: function(e) {
clearInterval(timer);
}
});
$el.mouseout({
timer;
});
});
I want to suspend the function on mouseover and resume it on mouse out but I cant get the latter right. How can I resume it?
Thank you.

There are two ways:
Set a flag that the function being called by the interval checks, and have the function not do anything if it's "suspended."
Start the interval again via a new setInterval call. Note that the old timer value cannot be used for this, you need to pass in the code again.
Example of #1:
jQuery(function($) { // DOM is ready
var $el = $("header tr"),
tot = $el.length,
c = 0,
suspend = false; // The flag
var timer = setInterval(function() {
if (!suspend) { // Check it
$el.removeClass("current").eq(++c % tot).addClass("current");
}
}, 3000);
$el.first().addClass("current");
$el.on({
mouseenter: function(e) {
suspend = true; // Set it
},
mouseleave: function(e) {
suspend = false; // Clear it
}
});
});
Example of #2:
jQuery(function($) { // DOM is ready
var $el = $("header tr"),
tot = $el.length,
c = 0,
timer = 0;
// Move this to a reusable function
var intervalHandler = function() {
$el.removeClass("current").eq(++c % tot).addClass("current");
};
// Probably best to encapsulate the logic for starting it rather
// than repeating that logic
var startInterval = function() {
timer = setInterval(intervalHandler, 3000);
};
// Initial timer
startInterval();
$el.first().addClass("current");
$el.on({
mouseenter: function(e) {
clearInterval(timer); // Stop it
}
mouseleave: function(e) {
startInterval(); // Start it
}
});
});

Checkout these prototypes:
//Initializable
function Initializable(params) {
this.initialize = function(key, def, private) {
if (def !== undefined) {
(!!private ? params : this)[key] = (params[key] !== undefined) ? params[key] : def;
}
};
}
function PeriodicJobHandler(params) {
Initializable.call(this, params);
this.initialize("timeout", 1000, true);
var getTimeout = function() {
return params.timeout;
};
var jobs = [];
function Job(params) {
//expects params.job() function
Initializable.call(this, params);
this.initialize("timeout", getTimeout(), true);
this.initialize("instant", false);
var intervalID = undefined;
this.start = function() {
if (intervalID !== undefined) {
return;
}
if (this.instant) {
params.job(true);
}
intervalID = setInterval(function() {
params.job(false);
}, params.timeout);
};
this.stop = function() {
clearInterval(intervalID);
intervalID = undefined;
};
}
this.addJob = function(params) {
jobs.push(new Job(params));
return jobs.length - 1;
};
this.removeJob = function(index) {
jobs[index].stop();
jobs.splice(index, 1);
};
this.startJob = function(index) {
jobs[index].start();
};
this.stopJob = function(index) {
jobs[index].stop();
};
}
Initializable simplifies member initialization, while PeriodicJobHandler is able to manage jobs in a periodic fashion. Now, let's use it practically:
var pjh = new PeriodicJobHandler({});
//It will run once/second. If you want to change the interval time, just define the timeout property in the object passed to addJob
var jobIndex = pjh.addJob({
instant: true,
job: function() {
$el.removeClass("current").eq(++c % tot).addClass("current");
}
});
jQuery(function($) { // DOM is ready
var $el = $("header tr"),
tot = $el.length,
c = 0;
var timer = setInterval(function() {
$el.removeClass("current").eq(++c % tot).addClass("current");
}, 3000);
$el.first().addClass("current");
$el.on({
mouseenter: function(e) {
jobIndex.stop();
}
});
$el.mouseout({
jobIndex.start();
});
});

With Javascript, it is much easy and efficient.
You can change the interval in setInterval function.
It is checking whether suspend variable is false or true, here suspend variable is setting to true, if mouseEnter function is called and set to false if mouseLeave function is called.
var displayMsg = document.getElementById('msg').innerHTML;
var i = 0;
var suspend = false;
var sequence = setInterval(update, 100);
function update() {
if (suspend == false) {
var dispalyedMsg = '';
dispalyedMsg = displayMsg.substring(i, displayMsg.length);
dispalyedMsg += ' ';
dispalyedMsg += displayMsg.substring(0, i);
document.getElementById('msg').innerHTML = dispalyedMsg;
i++;
if (i > displayMsg.length) {
i = 0;
}
}
}
document.getElementById('msg').addEventListener('mouseenter', mouseEnter);
document.getElementById('msg').addEventListener('mouseleave', mouseLeave);
function mouseEnter() {
suspend = true;
}
function mouseLeave() {
suspend = false;
}
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
#msg {
width: 680px;
height: 100px;
border: 1px solid #ccc;
padding-left: 15px;
}
</style>
</head>
<body>
<div id="msg">
Today is only 15% discount. Hurry up to grab. Sale will end sooooooooooooon!!!!
</div>
<div id="output"></div>
<script src="marquee.js"></script>
</body>
</html>

Changer SetInterval Values After Interval

If I can try to make everyone understand what I am looking for, I am looking for the value of the interval to change to lets say "5000ms" after "1000ms" and then it would go on to the next value such as "2000ms" and repeat all over again! The current code I have is pretty much a stopwatch, It adds the number 1 to a paragraph every 1000ms. Any help is extremely appreciated!
<script>
function myFunction() {
clicks += 1;
}
setInterval(myFunction, 1000);
var clicks = 0;
function myFunction() {
clicks += 1;
document.getElementById("demo").innerHTML = clicks;
// connects to paragraph id
}
</script>
<p id="demo"></p>
<!--connects to getElementById-->

Don't use setInterval - this functions will perform the action in any given interval, which you set once.
Use setTimeout instead. Which performs the action only once after given interval, and then call it again and again with different interval values.

what about this
<script>
var clicks = 0;
myFunction(1000);
function myFunction( currentInterval ) {
clicks ++;
document.getElementById("demo").innerHTML = clicks;
if ( currentInterval == 1000 )
{
currentInterval = 5000;
}
else if ( currentInterval == 5000 )
{
currentInterval = 2000;
}
else
{
currentInterval = 1000;
}
setTimeout( function(){ myFunction( currentInterval ) }, currentInterval );
}
</script>
<p id="demo"></p>

you should try using recursive timeout instead of interval
var timeout = 1000;
var timer;
function startTimer() {
clearTimeout(timer);
timer = setTimeout(function() {
console.log('tick');
startTimer();
}, timeout);
}
startTimer();
// timeout = 2000
// timeout = 500
// clearTimeout(timer); to cancel
<script src="https://getfirebug.com/firebug-lite-debug.js"></script>

This might look a little complicated but you can try something like this:
JSFiddle.
(function() {
var interval = null;
var limit = 5;
function initInterval(callback, index) {
var msToSec = 1000;
if (interval) {
clearInterval();
}
console.log("Delay: ", index)
interval = setInterval(callback, index * msToSec);
}
function clearInterval() {
window.clearInterval(interval);
interval = null;
}
function resetInterval(callback, count) {
clearInterval();
initInterval(callback, count);
}
function main() {
var count = 1;
var notify = function() {
console.log("Hello World: ", count);
var _nextCount = ((count++) % limit) + 1;
if (count < 10) {
resetInterval(notify, _nextCount);
} else {
console.log("Stoping loop...");
clearInterval();
}
}
initInterval(notify, count);
}
main()
})()

How do I add a pause function to this pageChange timer?

Below in the code is an array of pages which is shuffled and then each of them is displayed in an iframe for a certain amount of time. I want to be able to start/stop the pageChange function using a button or a mouse click. Can anyone help me with this? Below is the working code, or check this fiddle: http://jsfiddle.net/xaa1qccm/ (Thanks to Nobe4)
var pages=[];
pages[0]="http://example.com/";
pages[1]="http://www.iana.org/domains/reserved";
pages[2]="http://en.wikipedia.org/wiki/Main_Page";
pages[3]="http://en.wikipedia.org/wiki/Randomness";
var shuffle = function(array){
var shuffledPages = [];
while(array.length){
shuffledPages.push(array.splice(Math.floor(array.length*Math.random()),1));
}
return shuffledPages;
}
var time = 3300;
var currentIndex = 0;
function pageChange() {
if(currentIndex == 0){
pages = shuffle(pages);
console.log(pages);
currentIndex = pages.length;
}
currentIndex--;
document.getElementById("frame").src=pages[currentIndex];
console.log(currentIndex);
setTimeout(function() { pageChange(); }, time);
};
pageChange();

A variable which can be set to determine if the rotator is running, and setting that to true or false:
var isRunning = true;
....
<button onclick="isRunning = false">stop</button>
<button onclick="isRunning = true">start</button>
And check that inside your method:
function pageChange() {
if(isRunning){
...
}
setTimeout(function() { pageChange(); }, time);
};
Live example: http://jsfiddle.net/xaa1qccm/1/

You may add a start/stop variable so as to check the status :
[...]
var time = 3300;
var currentIndex = 0;
var stop = 0;
function pageChange() {
if(currentIndex == 0){
pages = shuffle(pages);
console.log(pages);
currentIndex = pages.length;
}
if (stop == 0)
{
currentIndex--;
document.getElementById("frame").src=pages[currentIndex];
console.log(currentIndex);
setTimeout(function() { pageChange(); }, time);
}
};
function startStop()
{
if (stop == 0){
stop = 1;
}
else{
stop = 0;
pageChange();
}
}
[...]
And then you call startStop() on the click event of the button you want
Edit : Here is a jsfiddle