We Keep Coding

How to set interval to always last Xs when clicked on carousel button (vanilla JavaScript)

I have made custom carousel (for learning) on this web page. Carousel has 2 buttons (next and previous) and dots (each dot is 1 picture). It all works fine, but there is one problem. I want to make automatic loop carousel (to loop through images in interval of X seconds). Now i am using setInterval(nextImgShow, 2000);. But every time i click on either button (next, previous, dots) the interval changes.
Example: I have interval of 2s. If i click on a button when 1,5s has passed, the next image will only show for 0,5s. If i click it right away at 0,5s, the next image will show for 1,5s.
I already try to fix this with clearInterval();, but it does not change a thing. I also try to use clearInterval(); and than set interval again setInterval(nextImgShow, 2000); (on every button), but no luck.
I also try to use setTimeout(); but again nothing.
My wish is: If interval is 2s, when i click on either of buttons, i want to reset/set my interval back to 2s. So that every image is displayed for 2s, no matter when the button was clicked.
Can anyone help me solve this?
Below is JavaScript code and link to my web page, so you can see.
LINK: Link to page, so you can see demo
// navigation selection
const navigation = document.querySelector("ul.navigation");
const navigationToggleButton = document.querySelector(".navigation-toggle");
const navigationList = document.querySelectorAll(".navigation a");
// background image selector
const backgroundImgDiv = document.querySelector(".bg");
const previousImgBtn = document.querySelector(".prev");
const nextImgBtn = document.querySelector(".next");
const imgDotBtn = Array.from(document.querySelectorAll(".dot"));
const arrImg = ['url("img/0.jpg")', 'url("img/1.jpg")', 'url("img/2.jpg")', 'url("img/3.jpg")'];
const dot0 = document.querySelector(".dot-0");
const dot1 = document.querySelector(".dot-1");
const dot2 = document.querySelector(".dot-2");
const dot3 = document.querySelector(".dot-3");
let startImgIndex = 0;
let currentIndex = 0;
// navigation functions
function toggleNav() {
navigation.classList.toggle("active");
}
function navLink() {
navigation.classList.remove("active");
}
// background image functions
function nextImgShow() {
startImgIndex++;
if (startImgIndex === arrImg.length) {
startImgIndex = 0;
}
currentIndex = startImgIndex;
backgroundImgDiv.style.backgroundImage = arrImg[startImgIndex];
toggleDotActive(currentIndex);
}
function previousImgShow() {
startImgIndex--;
if (startImgIndex === -1) {
startImgIndex = (arrImg.length - 1);
}
currentIndex = startImgIndex;
backgroundImgDiv.style.backgroundImage = arrImg[startImgIndex];
toggleDotActive(currentIndex);
}
function dotBtnNavigate() {
if (this.classList.contains("dot-0")) {
dotBtnSet(0);
} else if (this.classList.contains("dot-1")) {
dotBtnSet(1);
} else if (this.classList.contains("dot-2")) {
dotBtnSet(2);
} else if (this.classList.contains("dot-3")) {
dotBtnSet(3);
}
}
function dotBtnSet (number) {
backgroundImgDiv.style.backgroundImage = arrImg[number];
startImgIndex = number;
currentIndex = number;
toggleDotActive(currentIndex);
}
function toggleDotActive(currentIndex) {
switch(currentIndex) {
case 0:
dot0.classList.add("dot-active");
dot1.classList.remove("dot-active");
dot2.classList.remove("dot-active");
dot3.classList.remove("dot-active");
break;
case 1:
dot0.classList.remove("dot-active");
dot1.classList.add("dot-active");
dot2.classList.remove("dot-active");
dot3.classList.remove("dot-active");
break;
case 2:
dot0.classList.remove("dot-active");
dot1.classList.remove("dot-active");
dot2.classList.add("dot-active");
dot3.classList.remove("dot-active");
break;
case 3:
dot0.classList.remove("dot-active");
dot1.classList.remove("dot-active");
dot2.classList.remove("dot-active");
dot3.classList.add("dot-active");
break;
default:
break;
}
}
// navigation events
navigationToggleButton.addEventListener("click", toggleNav);
navigationList.forEach(item => item.addEventListener("click", navLink));
// background image event
nextImgBtn.addEventListener("click", nextImgShow)
previousImgBtn.addEventListener("click", previousImgShow);
imgDotBtn.forEach(btn => btn.addEventListener("click", dotBtnNavigate));
// for touch devices (carousel navigate)
const gestureZone = document.querySelector('.img-wrap');
let touchstartX = 0;
let touchstartY = 0;
let touchendX = 0;
let touchendY = 0;
// for touch devices function (carousel navigate)
function handleGesture() {
if (touchendX <= touchstartX) {
nextImgShow();
}
if (touchendX >= touchstartX) {
previousImgShow();
}
}
setInterval(nextImgShow, 2000);
// navigation events
navigationToggleButton.addEventListener("click", toggleNav);
navigationList.forEach(item => item.addEventListener("click", navLink));
// background image event
nextImgBtn.addEventListener("click", nextImgShow);
previousImgBtn.addEventListener("click", previousImgShow);
imgDotBtn.forEach(btn => btn.addEventListener("click", dotBtnNavigate));
// for touch devices events (carousel navigate)
gestureZone.addEventListener('touchstart', function(event) {
touchstartX = event.changedTouches[0].screenX;
touchstartY = event.changedTouches[0].screenY;
}, false);
gestureZone.addEventListener('touchend', function(event) {
touchendX = event.changedTouches[0].screenX;
touchendY = event.changedTouches[0].screenY;
handleGesture();
}, false);

You should be passing the interval ID (returned from setInterval) to the clear interval function. For example:
let myIntervalID = setInterval(nextImgShow, 2000);
Then you can clear the interval doing clearInterval(myIntervalID) just make sure the variable myIntervalID is in scope when you clear it.
Your clearInterval wasn't actually clearing the interval so you ran into this problem. Once you correctly clear the interval (like above) and call the interval again (kinda like resetting the interval) your image will show for the full interval

You should assign the setInterval to a variable and use clearInterval when the user clicks on one of the buttons to change the image and then set the interval again.
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script>
var change;
var i = 1;
var numOfImages = 3;
$(document).ready(function(){
document.getElementById("img1").classList.add("active");
change = setInterval(function(){
changeImage();
}, 2000);
});
function changeImage(){
var elem = document.getElementById("img"+i);
elem.style.display = "none";
i++;
if(i>numOfImages){
i = 1;
}
var elemToBeShown = "#img"+i;
$(elemToBeShown).show();
}
</script>
<style>
.images{
width: 50%;
margin-left: 40%;
}
#img2{
display: none;
}
#img3{
display: none;
}
.button{
border-radius: 50%;
height: 25px;
width: 25px;
margin: 0px 15px 15px 15px;
background-color: green;
display: inline-block;
}
.button:hover{
cursor: pointer;
background-color: blue;
}
</style>
</head>
<body>
<div class="images">
<img id="img1" src="data:image/jpeg;base64,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" width="125" height="125"/>
<img id="img2" src="data:image/jpeg;base64,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" width="125" height="125"/>
<img id="img3" src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRkoieaGln2U5aMZQZibEmbva3LVpVVOw-GbcizRKfmZzog4B5lnw" width="125" height="125"/>
</div>
<div style="width: 100%; text-align: center; margin-top: 25px;">
<div class="button" id="button1"></div>
<div class="button" id="button2"></div>
<div class="button" id="button3"></div>
</div>
<script>
$('.button').click(function(e){
var buttonid = $(this).attr('id');
var imgid = parseInt(buttonid.substring(6, buttonid.length), 10);
if(i!=imgid){
clearInterval(change);
document.getElementById("img"+i).style.display = "none";
document.getElementById("img"+imgid).style.display = "block";
i = imgid;
change = setInterval(function(){
changeImage();
}, 2000);
}
});
</script>
</body>
</html>

Set Interval Issue on Counter

I need to set up a simple counter in a div element, I've done a simplified version of the code below but the counter doesn't fire, and I can't work out why it isn't working
Codepen is here: https://codepen.io/emilychews/pen/rzJXpB
Code is below.
JS
var div1 = document.getElementById("div1");
function theCounter() {
var counter = 0;
div1.innerHTML = counter;
counter++;
}
setInterval(theCounter, 1000);
CSS
#div1 {
width: 50px;
height: 50px;
background: blue;
color: white;
}
HTML
<div id="div1"></div>

The counter does fire, but you are resetting its value every time it is called. You could pull the counter variable out of the theCounter function to make it work.
var div1 = document.getElementById("div1");
var counter = 0;
function theCounter() {
div1.innerHTML = counter;
counter+=1;
}
setInterval(theCounter, 1000);
Here's the updated pen: https://codepen.io/Nisargshah02/pen/mMXNjp

Perform click on one div after the other

I hope you understand my problem.
At the moment I have a JS-function that choses randomly a div of a specific Html-Class.
Now i would like to rewrite the function that it picks one div after the other, just like they are ordered in the HTML-content.
How can I do this?
For information: the random selection is made with jquery and looks like this:
function pickrandom() {
var elems = $(".classname");
if (elems.length) {
var keep = Math.floor(Math.random() * elems.length);
console.log(keep);
$(elems[keep]).click();
}
}
Thanks

$(document).on('click', '.classname', function(){
var self = $(this);
var total_items = $('.classname').length; // 10
var index = self.index(); //2 for 3rd element
if (index < total_items) {
setTimeout(function () {
$('.classname').eq(index+1).trigger('click');
}, 3000);
}
});
this will call the next clicks in 3 sec interval
i don't know why you are using a randomizer function.you can allow the user to make that click

Hopefully this helps you - can't see your markup, but it should get you on the right track. I've also changed your .click() to a .trigger('click') which should be quite a bit more dependable.
JavaScript
function pickrandom() {
var elems = $(".classname");
if (elems.length) {
var curTarget = Math.floor(Math.random() * elems.length);
console.log(curTarget);
$(elems[curTarget]).trigger('click');
// Find index of our next target - if we've reached
// the end, go back to beginning
var nextTarget = curTarget + 1;
if( nextTarget > elems.length ) {
nextTarget = 0;
}
// Wait 3 seconds and click the next div
setTimeout( function() { $(elems[nextTarget]).trigger('click'); }, 3000 );
}
}

$("div").click(function() {
var el = $(this);
setTimeout(function() {
console.log(el.text());
el.toggleClass("click");
}, 2000);
});
var random = Math.floor((Math.random() * $("div").length) + 1);
var index = random - 1;
console.log("Random number: ", random);
var clicker = setInterval(function() {
if (index === $("div").length) {
clearInterval(clicker);
console.log("cleared interval");
} else {
$("div").eq(index).click();
index++;
}
}, 2000)
div {
height: 50px;
width: 100%;
border: 2px solid black;
background-color: lightgreen;
margin-bottom: 10px;
text-align: center;
font-size: 30px;
}
.click {
background-color: lightblue;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>
Div 1
</div>
<div>
Div 2
</div>
<div>
Div 3
</div>
<div>
Div 4
</div>
<div>
Div 5
</div>
<div>
Div 6
</div>

fadeIn and fadeOut in javascript

I'm trying to write my own animations using JavaScript.
I wrote a function for fadeIn() as below, it changes the display property followed by a change in value of opacity. But it doesn't seem to be working.
What am I doing wrong?
function fadeIn(obj, defDisp) {
obj.style.opacity = 0;
obj.style.display = defDisp;
var opVal = 0;
while (opVal < 1) {
obj.style.opacity = opVal;
opVal += 0.1;
}
}
defDisp = Default value for display property

Without a timing interval, this will likely execute too fast for you to see it. The while loop, without a timeout feature, will execute in far less than a second, and you won't see it happen. It's like asking a computer to count to 10, it will do it in less than a millisecond.
Try using a setTimeout
http://www.w3schools.com/jsref/met_win_settimeout.asp
while(opVal < 1) {
setTimeout(function(){
obj.style.opacity = opVal;
opVal += 0.1;
}, 3000);
}
Alter the timer (3000 in this case) to something that makes your fade work for you. Every 1000 is a one second and your loop runs 10 times, so in this case it would be 30 seconds, likely too slow.
I would probably stick with a CSS transition however, as they tend to render better on all browsers.

var el = document.getElementById('fadein');
fadeIn(el);
function fadeIn(ele, defDisp) {
ele.style.opacity = 0;
ele.style.display = defDisp;
var opVal = 0;
var t = setInterval(function(){
if(opVal >= 1){
clearInterval(t);
}
ele.style.opacity = opVal;
opVal += 0.1;
}, 100);
}
#fadein{ background: #ccc; border:1px solid #ddd; padding: 10px }
<div id="fadein">Hello</div>

Use a function that calls itself after a delay.
function fadeIn(obj, defDisp) {
obj.style.opacity = 0;
obj.style.display = defDisp;
var last = +new Date(); // Keep track of the time to calculate the opacity
var fadeStep = function () {
obj.style.opacity = +obj.style.opacity + (new Date() - last) / 800;
last = +new Date();
if (+obj.style.opacity < 1) {
setTimeout(fadeStep, 16);
}
};
fadeStep();
}
var el = document.getElementById('box');
fadeIn(el, 'block');
#box{ padding: 1em; background: #009afd; color: #ffffff; display: none; }
<div id="box">Hello</div>
If you want the fade to be faster, replace 800 by anything lower and vice-versa.

Because html render and for loop use the same thread, so when you doing the for-loop,you can't see any changes until the function complete. You have to use a setTimeout or setInterval (or requestAnimationFrame which is introduced from html5) so you browser can have the control to change the properties on the page:
You can see a example from the snippet, although the second that use a setTimeout is faster than the first one, which use for loop, the first one will not change its color as browser not able to change color during for-loop.
And if you choose to use requestAnimationFrame like I do in the snippets, you can have a smooth animation while the time can also be controlled precisely.
function fadeIn() {
this.style.opacity = 0;
this.style.display = 'block';
var opVal = 0;
console.time("count");
while(opVal < 1) {
this.style.opacity = opVal;
opVal += 0.000001;
}
console.timeEnd("count");
}
// Accept target as the target to apply anim, time is total anim time in ms.
function fadeInAlt(target, time) {
var opacity = 0;
var last = window.performance.now();
console.time("count2");
target.style.opacity = opacity;
target.style.display = 'block';
var fadeInFunc = function(timeStamp) {
if (opacity < 1) {
// Define the change by passed time.
var timePassed = timeStamp - last;
opacity += timePassed / time;
target.style.opacity = opacity;
last = timeStamp;
requestAnimationFrame(fadeInFunc);
} else {
console.timeEnd("count2");
return;
}
};
requestAnimationFrame(fadeInFunc);
}
var div = document.getElementById('test');
div.onclick = fadeIn;
var div2 = document.getElementById('test2');
div2.onclick = function() {
fadeInAlt(this, 3000);
};
#test {
background-color: red;
width: 30px;
height:30px;
}
#test2 {
background-color: blue;
width: 30px;
height:30px;
}
<div id="test"></div>
<div id="test2"></div>

Cannot set property innerHTML of null on appended child (div)

Before I learn some Unity I wanted to be able to create a simple Javascript game out of my own knowledge. So, I started experimenting with a timer and it worked. Then I wanted to add a div element to my HTML document and have its text change in response to the timer. So I wrote this code:
var counter = 0;
var seconds = 0;
$(document).ready(function(e) {
var element = document.createElement("div");
element.id = "text2";
document.getElementById("canvas").appendChild(element);
function gameActions() {
document.getElementById("canvas").innerHTML = seconds;
if (seconds == 1) document.getElementById("text2").innerHTML = "second";
else document.getElementById("text2").innerHTML = "seconds";
counter++;
if (counter % 50 == 0) {
seconds++;
}
}
setInterval(gameActions, 20);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="canvas" class="imgcenter" style="width: 500px; height: 400px; background-color: #eeffee;">
</div>
Basically I'm intending to change the text of the "parent" div which displays the number of seconds passed after the html page is fully loaded. But before that, I'm trying to create a div with id text2 to add it inside the div parent.This div should display the word "seconds" depending on the time (basically display "second" when the seconds variable is 1, and "seconds" when not)
Where "imgcenter" is only CSS to specify auto margin. The error is that, whenever I run this on Chrome, I get:
Uncaught TypeError: Cannot set property 'innerHTML' of null
Am I correct to assume the div is not being added? Am I missing a step in the addition? Please let me know what you think the error is, thank you

This code:
var element = document.createElement("div");
element.id = "text2";
document.getElementById("canvas").appendChild(element);
… puts the element you are trying to target inside the canvas div.
This code:
document.getElementById("canvas").innerHTML = seconds;
… destroys everything in that element and replaces it with the HTML in the seconds variable.
Am I correct to assume the div is not being added?
No. The div is added, but then you destroy it before trying to do anything with it.

In your line document.getElementById("canvas").innerHTML = seconds; you are replacing your complete innterHTML of canvas. By that your element text2 is removed again.
If you want to show the unit independently from the seconds in it's own element, you should create an element unitfor example like this:
var counter = 0;
var seconds = 0;
$(document).ready(function (e) {
var element = document.createElement("div");
var unit = document.createElement("div"); // create a second element unit
element.id = "text2";
unit.id = "unit"; // asign the id unit
document.getElementById("canvas").appendChild(element);
document.getElementById("canvas").appendChild(unit);
function gameActions() {
document.getElementById("unit").innerHTML = seconds; // replace the unit with the valuen of seconds
if (seconds == 1) document.getElementById("text2").innerHTML = "second";
else document.getElementById("text2").innerHTML = "seconds";
counter++;
if(counter % 50 == 0) {
seconds++;
}
}
setInterval(gameActions, 20);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="canvas" class="imgcenter" style="width: 500px; height: 400px; background-color: #eeffee;">
</div>

You are removing the element you added when you replace the inner HTML of the canvas. It would be better if you just updated the entire contents with the entire string instead of creating a separate element. I would also wrap it in an IIFE so that the variables don't leak into the global scope.
(function () {
var counter = 0;
var seconds = 0;
var canvas = document.getElementById("canvas");
function gameActions() {
canvas.innerHTML = seconds + " second" + (seconds > 1 ? "s" : "");
counter++;
if (counter % 50 == 0) {
seconds++;
}
}
$(function() {
setInterval(gameActions, 20);
});
})();
http://jsfiddle.net/1unn153b/