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Resetting a Timer Back to 0 from Counter?

I have been googling for a solution for this problem, but many suggestions that I have found either freezes the counter or does nothing. counter.innerHTML = 0 just resumes where it left off after a second.
Here is my code:
let reset = document.getElementById('reset')
let counter = document.getElementById('counter')
let num = 0;
let timer = setInterval(countUp, 1000);
function countUp() {
counter.innerHTML = num++
}
//Reset timer
reset.addEventListener('click', stuff)
function stuff() {
clearInterval(timer)
}

What you have is mostly working, you just need to
clear the internal
reset the innerHtml to 0
let reset = document.getElementById('reset')
let counter = document.getElementById('counter')
let num = 0;
let timer = setInterval(countUp, 1000);
function countUp() {
counter.innerHTML = num++
}
//Reset timer
reset.addEventListener('click', stuff)
function stuff() {
counter.innerHTML = 0;
clearInterval(timer)
}
<button id="reset">reset</button>
<div id="counter" />

It's probably useful to put the logic that changes what you see in the page content in its own function: this will help you think about each part of the problem independently:
let resetBtn = document.getElementById('reset');
let counter = document.getElementById('counter');
let num = 0;
// Start the timer
let timer = setInterval(countUp, 1000);
// Use this to update the DOM (page content)
function updateUI () {
counter.textContent = num;
}
function countUp () {
// Increment the number
num += 1;
// Update the DOM
updateUI();
}
function reset () {
// Stops the interval
clearInterval(timer);
// Reset the number
num = 0;
// Update the DOM
updateUI();
}
// Update the UI the first time (before the counter reaches 1)
updateUI();
// Add the reset functionality to the button
resetBtn.addEventListener('click', reset);
<div id="counter"></div>
<button id="reset">Reset</button>

Restart Timer Using Javascript

I try to use JavaScript to set timer for my quiz.(setInterval) but if I finish the quiz earlier and click on start button gain, the time will start counting at the time I stop the quiz. How can I restart the time after I click on the start button again? .
<script>
var seconds = 40;
if (localStorage.getItem("counter")) {
if (localStorage.getItem("counter") <= 0) {
var value = seconds;
alert(value);
} else {
var value = localStorage.getItem("counter");
}
} else {
var value = seconds;
}
document.getElementById("divCounter").innerHTML = value;
var counter = function() {
if (value <= 0) {
localStorage.setItem("counter", seconds);
value = seconds;
} else {
value = parseInt(value) - 1;
localStorage.setItem("counter", value);
}
document.getElementById("divCounter").innerHTML = value;
};
var interval = setInterval(function() { counter(); }, 1000);
</script>

Based on your current code what you need to do to reset the counter is set value=seconds and removing the current value in localStorage.
So assuming you have a button like this in your HTML:
<button type"button" onclick="resetCounter()">Reset</button>
you can add a resetCounter() function in your code:
var resetCounter = () => {
value = seconds;
localStorage.removeItem("counter");
};

timer starts automatically instead of on a button press in javascript

I'm quite new to javascript so the answer is probably quite easy but anyways
I'm trying to make a simple click speed test but i cant get the timer to start when the user presses the click me button, so i resorted to just starting it automatically. if anyone can help me to start it on the button press it will be much appreciated
HTML code:
<button id="click2" onclick="click2()">Click Me!</button><br>
<span id="clicksamount">0 Clicks</span><br><br>
<span id="10stimer">10s</span>
JS code:
var click = document.getElementById("click2");
var amount = 0;
var seconds = 10;
var endOfTimer = setInterval(click2, 1000);
function click2() {
seconds--;
document.getElementById("10stimer").innerHTML = seconds + "s";
if (seconds <= 0) {
var cps = Number(amount) / 10;
document.getElementById("clicksamount").innerHTML = "You got " + cps + " CPS!";
document.getElementById("click2").disabled = true;
document.getElementById("10stimer").innerHTML = "Ended";
clearInterval(seconds);
}
}
document.getElementById("click2").onclick = function() {
amount++;
document.getElementById("clicksamount").innerHTML = amount + " Clicks";
}

It looks like you're overwriting your onclick function on the button with id click2 with the lowest 4 lines.
Also, you call clearInterval() with the seconds variable instead of the actual interval, which is referenced by endOfTimer.
I'd suggest to have a separated timer management in a function which you call only on the first click of your button.
See JSFiddle
<button id="clickbutton" onclick="buttonClick()">Click Me!</button><br>
<span id="clicksamount">0 Clicks</span><br><br>
<span id="secondcount">10s</span>
// We will have timerStarted to see if the timer was started once,
// regardless if it's still running or has already ended. Otherwise
// we would directly restart the timer with another click after the
// previous timer has ended.
// timerRunning only indicates wether the timer is currently running or not.
var timerStarted = false;
var timerRunning = false;
var seconds = 10;
var clickAmount = 0;
var timer;
function buttonClick() {
if (!timerStarted) {
startTimer();
}
// Only count up while the timer is running.
// The button is being disabled at the end, therefore this logic is only nice-to-have.
if (timerRunning) {
clickAmount++;
document.getElementById("clicksamount").innerHTML = clickAmount + " Clicks";
}
}
function startTimer() {
timerStarted = true;
timerRunning = true;
timer = setInterval(timerTick,1000);
}
function timerTick() {
seconds--;
document.getElementById("secondcount").innerHTML = seconds + "s";
if (seconds <= 0) {
timerRunning = false;
clearInterval(timer);
var cps = Number(clickAmount) / 10;
document.getElementById("clickbutton").disabled = true;
document.getElementById("clicksamount").innerHTML = "You got " + cps + " CPS (" + clickAmount + "clicks in total)!";
}
}

I made some changes to your code. Effectively, when the user clicks the first time, you start the timer then. The timer variables is null until the first the user clicks.
var click = document.getElementById("click2");
var noOfClicks = 0;
var seconds = 10;
var timer = null;
function doTick(){
seconds--;
if(seconds<=0){
seconds = 10;
clearInterval(timer);
document.getElementById("10stimer").innerHTML= "Ended"
timer=null;
document.getElementById("click2").disabled = true;
}
updateDisplay()
}
function updateClicks(){
if(!timer){
timer=setInterval(doTick, 1000);
clicks= 0;
seconds = 10;
}
noOfClicks++;
updateDisplay();
}
function updateDisplay(){
var cps = Number(noOfClicks) / 10;
document.getElementById("clicksamount").innerHTML = "You got " + cps + " CPS!";
document.getElementById("10stimer").innerHTML =seconds;
}
click.addEventListener('click', updateClicks)
https://jsbin.com/bibuzadasu/1/edit?html,js,console,output

function timer(startEvent, stopEvent) {
let time = 0;
startEvent.target.addEventListener(startEvent.type, () => {
this.interval = setInterval(()=>{
time++;
}, 10); // every 10 ms... aka 0.01s
removeEventListener(startEvent.type, startEvent.target); // remove the listener once we're done with it.
stopEvent.target.addEventListener(startEvent.type, () => {
clearInterval(this.interval); // stop the timer
// your output function here, example:
alert(time);
removeEventListener(stopEvent.type, stopEvent.target); // remove the listener once we're done with it.
});
});
}
Use event listeners rather than onclicks
usage example:
HTML
<button id="mybutton">Click me!</button>
JS
/* ABOVE CODE ... */
let mybutton = document.getElementById("mybutton");
timer(
{target: mybutton, type: "click"},
{target: mybutton, type: "click"}
);
function timer(startEvent, stopEvent) {
let time = 0;
startEvent.target.addEventListener(startEvent.type, () => {
this.interval = setInterval(()=>{
time++;
}, 10); // every 10 ms... aka 0.01s
removeEventListener(startEvent.type, startEvent.target); // remove the listener once we're done with it.
stopEvent.target.addEventListener(startEvent.type, () => {
clearInterval(this.interval); // stop the timer
// your output function here, example:
alert(time);
removeEventListener(stopEvent.type, stopEvent.target); // remove the listener once we're done with it.
});
});
}
let mybutton = document.getElementById("mybutton");
timer(
{target: mybutton, type: "click"},
{target: mybutton, type: "click"}
);
<button id="mybutton">Click me!</button>

//state initialization
var amount = 0;
var seconds = 10;
var timedOut=false;
var timerId=-1;
//counters display
var clicksDisplay= document.getElementById("clicksamount");
var timerDisplay= document.getElementById("10stimer");
function click2(e){
//first click
if(timerId===-1){
//start timer
timed();
}
//still in time to count clicks
if(!timedOut){
amount++;
clicksDisplay.innerText=amount +" Clicks";
}
}
function timed(){
//refresh timer dispaly
timerDisplay.innerText=seconds+"s";
seconds--;
if(seconds<0){
//stop click count
timedOut=true;
}else{
//new timerId
timerId=setTimeout(timed,1000);
}
}

Enable button when counter reaches zero

I have a button its disabled and i want to put a counter inside it, what i want to do is when the counter reaches zero it get enabled, how can i do that? in the code below the counter doesn't appear inside the button and i don't want the reset button i just want the button to be enabled when it reaches zero, here is what i have tried so far:
function Countdown()
{
this.start_time = "00:30";
this.target_id = "#timer";
this.name = "timer";
this.reset_btn = "#reset";
}
Countdown.prototype.init = function()
{
this.reset();
setInterval(this.name + '.tick()',1000)
}
Countdown.prototype.reset = function()
{
$(this.reset_btn).hide();
time = this.start_time.split(":");
//this.minutes = parseInt(time[0]);
this.seconds = parseInt(time[1]);
this.update_target();
}
Countdown.prototype.tick = function()
{
if(this.seconds > 0) //|| this.minutes > 0)
{
if(this.seconds == 0)
{
// this.minutes = this.minutes - 1;
this.seconds = 59
} else {
this.seconds = this.seconds - 1;
}
}
this.update_target()
}
Countdown.prototype.update_target = function()
{
seconds = this.seconds;
if (seconds == 0) $(this.reset_btn).show();
else if(seconds < 10) seconds = "0" + seconds;
$(this.target_id).val(this.seconds)
}
timer = new Countdown();
timer.init();
$(document).ready(function(){
$("#reset").click(function(){
//timer = new Countdown();
timer.reset();
});
});
.hidden {
display: none;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<button type="text" id="timer" disabled>Counter should be inside me, and enable me when it reaches 0</button>
<button id="reset">Reset</button>

This is much simpler than what you've got. Just use window.setTimeout().
Keep in mind that tracking time to a high precision is not super reliable in a browser. You may want to look at moment.js or use performance.now() for an easier API to handle that.
// Get refreence to span and button
var spn = document.getElementById("count");
var btn = document.getElementById("btnCounter");
var count = 5; // Set count
var timer = null; // For referencing the timer
(function countDown(){
// Display counter and start counting down
spn.textContent = count;
// Run the function again every second if the count is not zero
if(count !== 0){
timer = setTimeout(countDown, 1000);
count--; // decrease the timer
} else {
// Enable the button
btn.removeAttribute("disabled");
}
}());
<button id="btnCounter" disabled>Time left: <span id="count"></span></button>

How to stop countdown after a few rounds?

var secondsP = document.getElementById('seconds');
var btn1 = document.getElementById("btnSurrender");
var clock = null;
btn1.addEventListener("click", surrender);
function timer () {
clearInterval(clock);
var start = new Date().getTime();
clock = setInterval(function() {
var seconds = Math.round(15 - (new Date().getTime() - start) / 1000);
if (seconds >= 0) {
secondsP.textContent = seconds;
} else {
clearInterval(clock);
}
if (seconds === 0) {
}
}, 1000);
}
function surrender(){
clearInterval(clock);
secondsP.textContent = 0;
setTimeout(timer,2000);
}
timer();
setInterval(timer, 17000);
<html>
<head>
<style>
</style>
<script src="/scripts/snippet-javascript-console.min.js?v=1"></script>
</head>
<body>
<p id="seconds">15</p>
<button id= "btnSurrender">end now</button>
</body>
</html>
I need help with my little problem. I made a stopwatch which counts down 15 seconds. After this 15 seconds, it waits two seconds and starts again. You have option to stop counting when you want to, using "end now" button (then it'll start again after 2 sec). Now, my question is: how can I make a function which is going to stop whole counting after 3/4 rounds?

You restart the clock in surrender() using the call setTimeout(timer, 2000). All you need to do is add an if statement inside that function testing a variable that controls how many times you have run the timer, and then call/not call timer() accordingly. Here is a working example of it: https://jsfiddle.net/L38q6k5d/, but just to give you an idea of how it would work:
At the top of the js file:
var timesRun = 0
var timerInterval = null;
Inside the surrender function:
timesRun += 1 // Increment it each time the timer ends
if (timesRun > 4) { // If the timer has run less than 4 times
return; // this will stop the function here, so we dont start the timer again
}
setTimeout(timer, 2000); // Reset the timer
Inside the timer function,
if (timesRun > 1) {
clearInterval(timerInterval);
return; // end the function here
}
When starting the initial timer:
timer();
timerInterval = setInterval(timer, 17000);
Complete JS:
var secondsP = document.getElementById('seconds');
var btn1 = document.getElementById("btnSurrender");
var clock = null;
var timerInterval = null;
// New Code
var numberOfTimesRun = 0; // this is where we keep track of how many times the timer has run
btn1.addEventListener("click", surrender);
function timer () {
clearInterval(clock);
// New Code
if (numberOfTimesRun > 1) {
clearInterval(timerInterval);
return; // end the function here
}
// End New Code
var start = new Date().getTime();
clock = setInterval(function() {
var seconds = Math.round(15 - (new Date().getTime() - start) / 1000);
if (seconds >= 0) {
secondsP.textContent = seconds;
} else {
clearInterval(clock);
numberOfTimesRun += 1; // so we know that 1 iteration of the timer has been completed
}
if (seconds === 0) {
}
}, 1000);
}
function surrender(){
clearInterval(clock);
secondsP.textContent = 0;
//New Code
numberOfTimesRun += 1;
if (numberOfTimesRun > 4) {
return; // end the function there
}
setTimeout(timer, 2000)
//End New Code
}
timer();
timerInterval = setInterval(timer, 17000);