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Making a timer with code that can easily be reset

I'm making a shot clock for my school's basketball team. A shot clock is a timer that counts down from 24 seconds. I have the skeleton for the timer right now, but I need to have particular key bindings. The key bindings should allow me to rest, pause, and play the timer.
var count=24;
var counter=setInterval(timer, 1000);
function timer()
{
count=count-1;
if (count <= 0)
{
clearInterval(counter);
return;
}
document.getElementById("timer").innerHTML=count + " secs";
}

I'm not sure what you meant by "rest" the timer, I interpret this as "pause", so:
Space = Pause / Play.
R = Reset.
var
count=24,
counter = setInterval(timer, 1000),
running = true;
function timer() {
count -= 1;
if (count <= 0) {
clearInterval(counter);
}
document.getElementById("timer").innerHTML = count + " secs";
}
window.addEventListener("keydown", function(e) {
switch(e.keyCode) {
case 32: // PLAY
running ? clearInterval(counter) : counter = setInterval(timer, 1000);
running = !running;
break;
case 82: // RESET
clearInterval(counter);
document.getElementById("timer").innerHTML = 24 + " secs";
count = 24;
running = false;
}
});
<div id="timer">24 secs</div>

I am not able to comment yet, but I recommend checking out this post Binding arrow keys in JS/jQuery
The linked post explains how to bind arrow keys using js/jquery. Using http://keycode.info/ you can find out the keycodes of your desired keys and replace the current values then continue to build your code from there.

Here is my code sample: http://codepen.io/anon/pen/vLvWJM
$(document).ready(function() {
var $timer = $('#timer');
var $timerStatus = $('#timerStatus');
var timerValue = 24;
var intervalId = null;
var timerStatus = 'stopped';
if(!$timer.length) {
throw 'This timer is missing a <div> element.';
}
$(document).keydown(function(k) {
if(k.which == 80) {
if(timerStatus === 'playing') {
clearInterval(intervalId);
timerStatus = 'stopped';
updateTimerStatus();
return;
}
intervalId = setInterval(function() {
playTimer();
timerStatus = 'playing';
updateTimerStatus();
}, 1000);
} else if(k.which == 82) {
clearInterval(intervalId);
resetTimer();
updateText();
timerStatus = 'stopped';
updateTimerStatus();
}
});
function playTimer() {
if(timerValue > 0) {
timerValue--;
updateText();
}
}
function resetTimer() {
timerValue = 24;
}
function updateText() {
$timer.html(timerValue);
}
function updateTimerStatus() {
$timerStatus.html(timerStatus);
}
});
<div id="timerStatus">stopped</div>
<div id="timer">24</div>

adding wait for a loop in javaScript

I wanna run a loop in javaScript like this
for (conditions) { do something; wait for a second
}
How to make the portion of the condition typed in bold (delaying the condition for a second) ?

timeTillWarning = 10;
setTimeout(looping, 1000);
function looping() {
if (count > 0) {
count--;
setTimeout(looping, 1000);
}
}

var i = 100;
var interval = setInterval(function () {
// do something
i--;
if (i == 0) clearInterval(interval);
}, 1000);

How can i clearInterval(myFunc) after myFunc has executed 5 times?

The purpose of the code below is to alert online shoppers that they must select a color (via a select/option menu) before putting an item into their basket. If they don't select a color (ie, make a selection) some blinking text displays alerting them.
I'm trying to have the text blink 3 times then stop. I tried using some counter vars but didn't work. How can I re-write this so the blink executes 3 times only?
function blink() {
if ($('.pleaseSelect').css('visibility') == 'hidden') {
$('.pleaseSelect').css('visibility', 'visible');
} else {
$('.pleaseSelect').css('visibility', 'hidden')
}
}
function showNotice() {
timerId = setInterval(blink, 200);
}
$('#addToCart').click(function() {
if ($("select > option:first").is(":selected")) {
showNotice();
} else {
clearInterval(showNotice);
$('.pleaseSelect').css('visibility', 'hidden');
}
})

Well you can have counter declared and incremented each time blink is called. then check if you have called blink three times, clear the interval. Also your showNotice function is not defined properly.
var counter = 0,
timerId;
function blink() {
if ($('.pleaseSelect').css('visibility') == 'hidden') {
$('.pleaseSelect').css('visibility', 'visible');
} else {
$('.pleaseSelect').css('visibility', 'hidden')
if (counter > 4) {
showNotice(false);
}
}
counter++;
}
function showNotice(show) {
if (show) {
timerId = setInterval(blink, 200);
} else {
clearInterval(timerId);
counter = 0;
}
}
$('#addToCart').click(function () {
if ($("select > option:first").is(":selected")) {
showNotice(true);
} else {
showNotice(false);
$('.pleaseSelect').css('visibility', 'hidden');
}
})
Here is working fiddle

function blink(){
var blinkCount = 0;
return function () {
if($('.pleaseSelect').css('visibility')== 'hidden'){
$('.pleaseSelect').css('visibility', 'visible');
} else {
$('.pleaseSelect').css('visibility', 'hidden')
}
blinkCount = blinkCount + 1;
if (blinkCount === 3) {
clearInterval(timerId);
}
}
}
the only thing is that timeId is global - bad practice... however you would have to refactor more of your code in order to correct that issue.

another option is to just fadIn and fadeOut rather than what you're doing.
It would look something like:
if(element.val() == ''){
element.fadeOut("fast");
element.fadeIn("fast");
element.fadeOut("fast");
element.fadeIn("fast");
element.fadeOut("fast");
element.fadeIn("fast");
}

How about this example? Use an anonymous function to call your blink method and keep decrementing a counter.
id = setInterval(function () {
counter--;
if (!counter) {
clearInterval(id);
}
blink();
}, 200);
See the JSFiddle for the complete context.

You can accomplish the desired behavior using variables within a private scope:
$('#addToCart').click(function(e) {
blink(e);
});
function blink(e) {
var blink_count = 0;
var timer = setInterval(function(e) {
blink_count++;
$('.pleaseSelect').toggle();
if (blink_count >= 6) {
clearInterval(timer);
blink_count = 0;
}
}, 200);
}

How do I correctly use setInterval and clearInterval to switch between two different functions?

For practice I am trying to display a number that increments from 0 - 9, then decrements from 9 - 0, and infinitely repeats.The code that I have so far seems to be close, but upon the second iteration the setInterval calls of my 2 respective functions countUp and countDown seem to be conflicting with each other, as the numbers displayed are not counting in the intended order... and then the browser crashes.Here is my code:
<!DOCTYPE html>
<html>
<head>
<title>Algorithm Test</title>
</head>
<body onload = "onloadFunctions();">
<script type = "text/javascript">
function onloadFunctions()
{
countUp();
setInterval(countUp, 200);
}
var count = 0;
function countUp()
{
document.getElementById("here").innerHTML = count;
count++;
if(count == 10)
{
clearInterval(this);
countDown();
setInterval(countDown, 200);
}
}
function countDown()
{
document.getElementById("here").innerHTML = count;
count--;
if(count == 0)
{
clearInterval(this);
countUp();
setInterval(countUp, 200);
}
}
</script>
From 0 - 9, up and down: <div id = "here"></div>
</body>
</html>

You need to capture the return value from setInterval( ... ) into a variable as that is the reference to the timer:
var interval;
var count = 0;
function onloadFunctions()
{
countUp();
interval = setInterval(countUp, 200);
}
/* ... code ... */
function countUp()
{
document.getElementById("here").innerHTML = count;
count++;
if(count === 10)
{
clearInterval(interval);
countUp();
interval = setInterval(countUp, 200);
}
}

#Claude, you are right, the other solution I proposed was too different from original code. This is another possible solution, using setInterval and switching functions:
function onloadFunctions() {
var count = 0;
var refId = null;
var target = document.getElementById("aux");
var countUp = function() {
target.innerHTML = count;
count ++;
if(count >= 9) {
window.clearInterval(refId);
refId = window.setInterval(countDown, 500);
}
}
var countDown = function() {
target.innerHTML = count;
count --;
if(count <= 0) {
window.clearInterval(refId);
refId = window.setInterval(countUp, 500);
}
}
refId = window.setInterval(countUp, 500);
}

clearInterval(this);. You can't do that. You need to save the return value from setInterval.
var interval;
function onloadFunctions()
{
countUp();
interval = setInterval(countUp, 200);
}
var count = 0;
function countUp()
{
document.getElementById("here").innerHTML = count;
count++;
if(count == 10)
{
clearInterval(interval);
countDown();
interval = setInterval(countDown, 200);
}
}
function countDown()
{
document.getElementById("here").innerHTML = count;
count--;
if(count == 0)
{
clearInterval(interval);
countUp();
interval = setInterval(countUp, 200);
}
}

try this:
...
<body onload = "onloadFunctions();">
<script>
var cup, cdown; // intervals
var count = 0,
here = document.getElementById("here");
function onloadFunctions() {
cup = setInterval(countUp, 200);
}
function countUp() {
here.innerHTML = count;
count++;
if(count === 10) {
clearInterval(cup);
cdown = setInterval(countDown, 200);
}
}
function countDown() {
here.innerHTML = count;
count--;
if(count === 0) {
clearInterval(cdown);
cup = setInterval(countUp, 200);
}
}
</script>
From 0 - 9, up and down: <div id = "here"></div>
</body>
you could also create a single reference to #here element. Use always === instead of ==

There are many ways to solve this problem, the following is my suggestion:
function onloadFunctions() {
var count = 0;
var delta = 1;
var target = document.getElementById("here");
var step = function() {
if(count <= 0) delta = 1;
if(count >= 9) delta = -1;
count += delta;
target.innerHTML = count;
window.setTimeout(step, 500);
}
step ();
}
PS: it's safer to use setTimeout than setInteval.

/** Tools */
const log = require('ololog').configure({
locate: false
})
let count = 0
let interval__UP
let interval__DOWN
function countUp () {
count++
log.green('countUp(): ', count)
if (count == 5) {
clearInterval(interval__UP)
interval__DOWN = setInterval(function () {
countDown()
}, 1000)
}
}
function countDown () {
count--
log.red('countDown(): ', count)
if (count == 0) {
clearInterval(interval__DOWN)
interval__UP = setInterval(function () {
countUp()
}, 3000)
}
}
function start () {
countUp()
log.cyan('start()')
interval__UP = setInterval(function () {
countUp()
}, 2000)
}
start()
Console Log shows it's working

Javascript Countdown Show Link

I'm trying to use this code to countdown from 10 seconds, then show a link.
x116=30;
FUNCTION countdown()
{
IF ((0 <= 100) || (0 > 0))
{
x116--;
IF(x116 == 0)
{
document.getElementById("dl").innerHTML = 'Download';
}
IF(x116 > 0)
{
document.getElementById("dl").innerHTML = 'Please wait <b>'+x116+'</b> seconds..';
setTimeout('countdown()',1000);
}
}
}
countdown();
I just know some really basic javascript. So could anyone tell me whats wrong with this? Nothing happens basically.

Try this:
var container = document.getElementById('dl');
var seconds = 10;
var timer;
function countdown() {
seconds--;
if(seconds > 0) {
container.innerHTML = 'Please wait <b>'+seconds+'</b> seconds..';
} else {
container.innerHTML = 'Download';
clearInterval(timer);
}
}
timer = setInterval(countdown, 1000);