Here's a simple countdown timer that counts from 9 down to 0.
The countdown works fine. But what if I want to pause it mid-flow and then restart from where it was paused?
I have tried (see code below) to interrupt the countdown, save the number it was at, and then restart the function from the new number. But the countdown goes haywire, and I can't see why. Any ideas?
PS. I could cut and paste a timer from elsewhere, but I'm doing this for the learning experience. I'm sure there are better ways to code a countdown timer in JS, but it's bugging me that I can't make THIS way work and think I must be missing something obvious.
Many thanks
var currentTimeInt = 10;
var minn = [];
var stop = 0;
// stop
function stopCounter() {
currentTime = document.getElementById('mins').textContent; // grabs the number of minutes at moment of pause.
stop = 1;
}
// restart
function restart() {
stop = 0;
currentTimeInt = parseInt(currentTime, 10); // converts that number into an integer we can use
document.getElementById("mins").innerHTML=currentTimeInt;
newMinutes(); // restarts the newMinutes function with the start time currentTimeInt set to the time the counter stopped at
}
function newMinutes() {
document.getElementById('mins').innerHTML= currentTimeInt; // displays the counter
for (aa = currentTimeInt-1; aa >= 0; aa--) {
minn.push(aa); // builds an array of numbers in descending order
document.getElementById('mins').innerHTML= minn[aa];
for (let bb=1; bb<=currentTimeInt; bb++) {
if (bb<currentTimeInt) {
setTimeout( function timer(){
if (stop == 0) { // checks if "stop!" has been clicked and returns false to stop the function if that is the case
document.getElementById('mins').innerHTML= minn[bb];
console.log(minn[bb]);
}
else {return false;}
}, bb*1000 );
}
}
}
console.log(currentTimeInt + " the end");
}
<span>Minutes: </span><span id= "mins"></span>
<button onclick="newMinutes()">Go!</button>
<button onclick="stopCounter()">Stop!</button>
<button onclick="restart()">Reset!</button>
You may try this as an example:
var timerId;
var counter;
function start() {
console.log('start');
if (!counter) {
reset();
} else {
loop();
}
}
function pause() {
console.log('pause');
if (timerId) {
clearInterval(timerId);
timerId = null;
}
}
function reset() {
console.log('reset');
pause();
counter = 10;
loop();
}
function loop() {
timerId = setInterval(function() {
if (0 >= counter) {
pause();
return;
}
console.log('counter', counter);
counter--;
}, 500);
}
<button onclick='start();'>Start</button>
<button onclick='pause();'>Pause</button>
<button onclick='reset();'>Reset</button>
Here is my little Countdown with START, PAUSE, RESUME, STOP & RESET features:
var jqcd_start_id = 'input#jqcd_start';
var jqcd_time_id = 'input#jqcd_time';
var jqcd_count_id = 'span#jqcd_count';
var jqcd_end_message = 'Time is up!';
var jqcd_countdown = '';
var jqcd_status = 'stopped';
var jqcd_current = '';
function jqcd(action){
if (action == 'start') {
if (jqcd_status == 'stopped') {
jqcd_updtv(jqcd_start_id, 'Pause');
jqcd_status = 'running';
jqcd_current = jqcd_countdown;
jqcd_updtt(jqcd_count_id, jqcd_countdown);
}
else if (jqcd_status == 'running') {
jqcd_updtv(jqcd_start_id, 'Resume');
jqcd_status = 'paused';
}
else if (jqcd_status == 'paused') {
jqcd_updtv(jqcd_start_id, 'Pause');
jqcd_status = 'running';
}
}
else if (action == 'stop') {
jqcd_updtv(jqcd_start_id, 'Start');
jqcd_status = 'stopped';
jqcd_updtt(jqcd_count_id, jqcd_end_message);
}
else if (action == 'reset') {
jqcd_updtv(jqcd_start_id, 'Start');
jqcd_status = 'stopped';
jqcd_updtt(jqcd_count_id, jqcd_countdown);
}
var a = jqcd_current.split(":");
var m = a[0];
var s = (a[1] - 1);
if (s < 0) {
if (parseInt(m) == 0) {
jqcd_updtv(jqcd_start_id, 'Start');
jqcd_status = 'stopped';
jqcd_updtt(jqcd_count_id, jqcd_end_message);
}
else {
m = m - 1;
s = 59;
}
}
if(s >= 0){
setTimeout(function(){
if (jqcd_status == 'running') {
m = (parseInt(m) < 10)? "0" + parseInt(m): m;
s = (parseInt(s) < 10)? "0" + parseInt(s): s;
jqcd_updtt(jqcd_count_id, m + ":" + s);
jqcd_current = m + ":" + s;
jqcd('');
}
}, 1000);
}
}
function jqcd_updtv(selector, value) {
if (selector != '') {
$(selector).val(value);
}
}
function jqcd_updtt(selector, value) {
if (selector != '') {
$(selector).text(value);
}
}
$(document).ready(function() {
jqcd_countdown = $(jqcd_time_id).val();
jqcd_updtt(jqcd_count_id, jqcd_countdown);
$(jqcd_time_id).keyup(function() {
jqcd_countdown = $(jqcd_time_id).val();
jqcd_updtt(jqcd_count_id, jqcd_countdown);
jqcd_updtv(jqcd_start_id, 'Start');
jqcd_status = 'stopped';
});
});
span#jqcd_count {
font-size: 20pt;
font-weight: bold;
}
input#jqcd_start,
input#jqcd_stop,
input#jqcd_reset {
font-size: 12pt;
font-weight: bold;
}
input#jqcd_start,
input#jqcd_stop,
input#jqcd_reset {
width: 100px;
}
span#jqcd_count {
font-family: "Lucida Console", Monaco, "Courier New", Courier, monospace !IMPORTANT;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<span id="jqcd_count">00:30</span><br><br>
<input type="button" id="jqcd_start" value="Start" onClick="jqcd('start')" />
<input type="button" id="jqcd_stop" value="Stop" onClick="jqcd('stop')" />
<input type="button" id="jqcd_reset" value="Reset" onClick="jqcd('reset')" /><br><br>
<input type="text" id="jqcd_time" value="00:10" />
<br><br>
It is pretty simple to customize. The first four variables in the JavaScript code can be adapted to work with your specific HTML.
If you want an action to take place every second, add your lines of code inside of the "jqcd_updtt" function.
The CSS is completely optional, of course.
The Countdown start time is set dynamically by altering the value in the "jqcd_time" field. If, however, you want to set a static value for the Countdown starting point, you can alter the variables inside the "$(document).ready(function() {" function at the end of the JavaScript code.
PS.
This Countdown has no maximum limit for minutes or seconds
What about keeping it KISS!
let i = 9,j
function chrono(){
if (i>=0){
now.innerText = i--
}
}
<h1><div id="now">⏰ Ready!</div>
<button onclick="setInterval(function(){ chrono() }, 1000);this.style.display='none'">Start</button>
<button onclick="i=10">Reset</button>
<button onclick="j=i;i=-1">Pause</button>
<button onclick="i=j">Continue</button>
This is the most basic example ready to be expanded, mostly there is no clearInterval.
The KISS principle states that most systems work best if they are kept
simple rather than made complicated; therefore simplicity should be a
key goal in design and unnecessary complexity should be avoided.
https://en.wikipedia.org/wiki/KISS_principle
Therefore, js incrementation and setInterval seems easy but they hide complex things.
An other approach using date.now() that provide an accurate unix timestamp based on the system clock, and the web audio api for beeping.
i = Date.now();j=i+10000;z.innerText="Target #"+j
function d(){
if(now.innerText < j){
now.innerText = Date.now()
k(3,603,80)
}
if(now.innerText > j){
now.innerHTML = "<b>TIME TRAVEL COMPLETE!</b>"
k(8,728,100)
}
}
setInterval(function(){ d() }, 100)
a=new AudioContext()
function k(w,x,y){
v=a.createOscillator()
u=a.createGain()
v.connect(u)
v.frequency.value=x
v.type="square"
u.connect(a.destination)
u.gain.value=w*0.01
v.start(a.currentTime)
v.stop(a.currentTime+y*0.001)
}
EPOCH: <out id="now"></out><h6 id="z">
The first issue here is that currentTime isn't globally defined, so it can't be accessed from within restart. Just put var currentTime; at the start of your file.
But you have another serious breaking issue in that you're using setTimeout in a really awkward way. You're creating multiple timeouts all at once and giving them a delay based on their relation tocurrentTimeInt. This has two problems. For one the use of two for loops isn't very efficient and also seems redundant as your inner for loop is just going to count up to the currentTimeInt anyway.
Secondly, you never clear (and probably won't be able to clear) the timeouts. That means when you restart your timer after pausing if any timeouts hadn't yet been fired, then your program will run those and make the minutes jump back and forth between the old timeouts and the new ones you create after unpausing.
I know in your comment you said you wanted to get this to work because you basically did the whole thing yourself, but it may not be worth continuing down this road. After looking at it some I think fixing your program would require it to be restructured, or else require it to be hacked in a way that makes it pretty inefficient. And if you're someone who's just learning Javascript, it's probably better to just start over and do it the right way anyway.
Below is an example of a better way using setInterval rather than setTimeout, but feel free to just try and figure it out on your own.
(There are ways you can improve the functionality of the code below, but it should be enough to get you the general idea)
var startTimeInt = 10;
var currentTimeInt = startTimeInt;
var interval = undefined;
// start the timer
function startCounter() {
if(!interval){
document.getElementById('mins').innerHTML = currentTimeInt;
interval = setInterval(newNumber, 1000) // set an interval
}
}
// stop
function stopCounter() {
// clear the interval
clearInterval(interval)
interval = undefined;
}
// reset the timer
function resetCounter(){
currentTimeInt = startTimeInt;
document.getElementById('mins').innerHTML = currentTimeInt;
//stopCounter(); startCounter();
}
// change the time and handle end of time event
function newNumber(){
currentTimeInt--; // decrement the current time
document.getElementById('mins').innerHTML = currentTimeInt;
if(currentTimeInt == 0){
console.log("Done");
stopCounter();
}
}
<span>Minutes: </span><span id= "mins"></span>
<button onclick="startCounter()">Go!</button>
<button onclick="stopCounter()">Stop!</button>
<button onclick="resetCounter()">Reset!</button>
Here is a working Snippet..
var paused = false;
var started = false;
var stopped = true;
var currentCount = 0;
var running = false;
interval = 1000;
maxCount = 10;
function start() {
if (stopped){
started = true;
paused= false;
stopped = false;
currentCount = maxCount;
loop(); running = true;
return;
}
paused= false;
}
function pause() {
paused= true;
}
function stop(){
paused = false;
started = false;
stopped = true;
running = false;
currentCount = 0;
}
function update(item){
document.getElementById("status").innerHTML = item;
//console.log(item);
--currentCount;
if(currentCount < 0){stop()}
}
function reset() {
currentCount = maxCount;
document.getElementById("status").innerHTML = currentCount;
}
function loop(){
if (!stopped){
if (!paused){update(currentCount);}
setTimeout(function(){loop()}, interval)
}
}
<button onclick='start();'>Start</button>
<button onclick='pause();'>Pause</button>
<button onclick='reset();'>Reset</button>
<button onclick='stop();'>Stop</button>
<div id="status"></div>
for anyone who want to re-use the code, simply change the value of timer and the render function to fit your project
var timer= 10;
var intervalID
// pause/stop
function stopTimer() {
clearInterval(intervalID);
intervalID= null;
}
// restart
function restart() {
stopTimer();
timer= 10;
render();
// Go(); //Optional
}
// start/resume
function Go() {
if(intervalID){
//if interval already created previously, exit function
return
}
intervalID = setInterval(
() => {
if(timer< 1){
//escape from interval so that counter dont go below 0
return stopTimer();
}
timer--;
render();
}, 1000); //1000 milisecond == 1 second
}
function render(){
// it is ok to run render redundantly as it does not mutate the data
// feel free to change this to fit your needs
console.log(timer);
document.getElementById("mins").innerHTML=timer;
}
render() //render once on load
<span>Minutes: </span><span id= "mins"></span>
<button onclick="Go()">Go!</button>
<button onclick="stopTimer()">Stop!</button>
<button onclick="restart()">Reset!</button>
I am trying to implement a fade in/fade out feature that runs on a button click depending if some data was changed. I am using angular but the ngAnimate I could not get to work so I want to do it with pure js. What I currently have will flash the text for a second, then do nothing. This is inside my controller.
var warningText = document.getElementById('warningText');
warningText.style.display = 'inline'
$scope.warningText = "Warning: No Data was updated.";
var op = 0.0;
var fadeIn = setInterval(function() {
if (op >= 1) {
clearInterval(fadeIn);
fadeOut(op);
}
warningText.style.opacity = op;
op += op * 0.1;
}, 50);
var fadeOut = function(op) {
setInterval(function() {
if (op <= 0.1) {
clearInterval(fadeOut);
warningText.style.display = 'none';
}
warningText.style.opacity = op;
op -= op * 0.1;
}, 50);
}
Your calculation of op is wrong as that will always be zero. Secondly the second function does not return the value from setInterval, so you'll never be able to clear that interval.
Here is how you could do it with just one interval, where the sign of the increments to the opacity is reversed every time the boundary value is reached:
var warningText = document.getElementById('warningText');
function flickerMessage(msg) {
var op = 0.1;
var increment = +0.1;
warningText.textContent = msg;
warningText.style.opacity = 0;
warningText.style.display = 'inline';
var timer = setInterval(function() {
op += increment;
warningText.style.opacity = op;
if (op >= 1) increment = -increment;
if (op <= 0) {
warningText.style.display = 'none';
clearInterval(timer); // end
}
}, 50);
}
flickerMessage('Warning you');
<div id="warningText" style="display:none; opacity: 0">warning text</div>
<hr>
Im having a little trouble fixing a problem i have with setInterval.
I have a function that runs when i click an element on my website that sets var pass = 1;
if you look in color1(); there is a set Interval that clears itself when pass > 0; so if pass = 1; then it should clear itself, it does, but only after running the interval one more time.
so it - runs setInterval, clears setInterval, then runs the rest of the code in setInterval. What i need, is for setInterval to clear without running the code again.
Thanks in advance
function color1() {
var pass = 1;
var counter = 2;
var animationSpeed = 800;
var $colorContent = '.color-container-1 .color-content-container'
var colorInterval = setInterval(function() {
if (pass > 0) {
clearInterval(colorInterval);
}
$($colorContent).fadeOut(0);
$(($colorContent + '-' + counter)).fadeIn(animationSpeed);
++counter
if (counter === $($colorContent).length + 1) {
counter = 1;
}
}, 3000);
}
It should be like below, you should return the function. Here you have cleared the interval but you haven't stopped the execution
var colorInterval = setInterval(function() {
if (pass > 0) {
clearInterval(colorInterval);
return; //stop here so that it doesn't continue to execute below code
}
$($colorContent).fadeOut(0);
$(($colorContent + '-' + counter)).fadeIn(animationSpeed);
++counter
if (counter === $($colorContent).length + 1) {
counter = 1;
}
}, 3000);
I am trying to make an image to fade out and then in. The problem is that when I use two functions, the image doesn't fade out but it immediately disappears. Is there anyone with amazing JavaScript skills to solve my problem?
Please do not tell me about jQuery because I already know how to do it using it, I only need to improve my JavaScript skills.
PS: I need also to understand why it doesn't work and how to make it work with as much details please.
Here is my code:
var el = document.getElementById("img1");
el.addEventListener("click", function() {
function fadeOut() {
el.style.opacity = 1;
function fade(){
var val = el.style.opacity;
if ((val -= .01) > 0){
el.style.opacity = val;
requestAnimationFrame(fade);
}
}
fade();
};
function fadeIn() {
el.style.opacity = 0;
function fade1() {
var val = el.style.opacity;
if ((val += .01) < 1){
el.style.opacity = val;
requestAnimationFrame(fade1);
}
}
fade1();
};
fadeIn();
fadeOut();
});
Thank you!
Still not the prettiest, but I have made just the minimum changes to your code to make it work: http://codepen.io/rlouie/pen/BzjZmK
First, you're assigning the opacity value back and forth repeatedly for no reason, which makes the code confusing to follow and also results in string concatenation instead of addition or subtraction, I have simplified this. Second, the functions were named the opposite of what they did, also confusing and fixed by me here. Finally, you ran both functions one after the other, so the second function set opacity to zero and then broke. Instead, I use a promise in your first function and resolve it when the animation completes.
That way the second function does not run until after the first one has completed animating.
var el = document.getElementById("img1");
el.addEventListener("click", function() {
function fadeOut() {
return new Promise(function (resolve, reject) {
let opacity = 1;
function fade(){
if ((opacity -= .01) > 0){
el.style.opacity = opacity;
requestAnimationFrame(fade);
} else {
resolve();
}
}
fade();
});
};
function fadeIn() {
let opacity = 0;
function fade1() {
if ((opacity += .01) < 1){
el.style.opacity = opacity;
requestAnimationFrame(fade1);
}
}
fade1();
};
fadeOut().then(fadeIn);
});
My proposal is:
start animation with fadein
when fadein finishes start the fadeout
var el = null;
function fadeIn(timestamp) {
var val = (+el.style.opacity == 0) ? 1 : +el.style.opacity;
if ((val -= .005) > 0) {
el.style.opacity = val;
window.requestAnimationFrame(fadeIn);
} else {
window.requestAnimationFrame(fadeOut);
}
}
function fadeOut(timestamp) {
var val = (+el.style.opacity == 0) ? 1 : +el.style.opacity;
if ((val += .005) < 1) {
el.style.opacity = val;
window.requestAnimationFrame(fadeOut);
}
};
window.onload = function () {
el = document.getElementById('img1');
el.addEventListener('click', function(e) {
window.requestAnimationFrame(fadeIn);
});
}
<img id="img1" src="http://www.loc.gov/pictures/static/data/highsm/banner.jpg">
Voor de fade in:
Function FadeIn() {
var milli = 3000; //duration
el = yourelement;
el.style.opacity = 1;
var a = 1 / (milli / 1000 * 16); //the -x
FadeIn_loop(a);
}
Function FadeIn_loop(a) {
if (el.style.opacity > 0.01) {
el.style.opacity = el.style.opacity - a;
setTimeout("FadeIn(" + el + ")", 16); //about 1/60 a second
} else {
el.style.opacity = 0;
}
}
Same thing for fade out, succes!
In your code are many things that does'nt seem to be right. First of get all those functions out of each other otherwise requestAnimationframe cant find the functions.
I've got a setInterval script that repeats logging "Hello world" 10 times.
I would like to make it stop for 1 second after repeating 10 times, then starting again and doing the process for ever.
here is what I have:
var i = 0;
var x = setInterval(function(){
console.log("Hello world");
i++;
if(i >= 10){
i = 0;
stopInterval()
}
},1000);
var stopInterval = function(){
clearInterval(x);
setTimeout(function(){
//restart the interval, but how do I do???
},1000);
};
However, it says stopInterval is not defined and I thought it was
So you need to use clearInterval and use the id that is returned from setInterval to clear it.
function myTimer() {
var i = 0,
interval = setInterval(function(){
console.log("Hello world");
i++;
if(i >=10){
clearInterval(interval);
window.setTimeout(myTimer, 1000);
}
},100);
}
https://developer.mozilla.org/en-US/Add-ons/Code_snippets/Timers
just with setTimeout and Recursion DEMO
var i = 1;
var delay = 500;
function callMe() {
console.log("Hello World"+i);
document.getElementById("pri").innerHTML = "Hello World " + i;
if (i == 11) {
i = 1;
delay = 1000;
console.log("......Restart");
document.getElementById("pri").innerHTML = "......Restart";
} else {
delay = 300;
}
setTimeout(callMe, delay);
++i;
}
window.onload = callMe;
<div id="pri"></div>