fadeIn and fadeOut in javascript - 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>

Related

Countdown timer counting too far

I am trying to make a game that tests how many times you can click on a div in a minute. I can not get my countdown to function properly. My countdown should stop at 0, but instead it keeps going after reaching 0. My code is below. Any ideas?
let div = document.getElementById("div");
let score = document.querySelector("h3");
let time = document.querySelector("span");
var jsTime = 60;
var jsScore = 0;
alert("Click inside the box as many times as you can in one minute. \n Ready?");
var clicker = div.addEventListener("click", function() {
jsScore++;
score.innerHTML = jsScore;
}, 1);
var i = 60;
setInterval(function() {
if (i > 1) {
jsTime--;
time.innerHTML = jsTime;
} else {
removeEventListener(clicker);
}
}, 1000);
#div {
text-align: center;
width: 100px;
height: 100px;
background: black;
color: white;
}
#container {
display: inline-block;
}
<h1>Click inside the box as many times as you can in one minute.</h1>
<br>
<div id="container">
<h2>Time:</h2><span>60</span>
<h2>Score:</h2>
<h3>0</h3>
</div>
<div id="div"></div>
You're decreasing the jsTime as long as i is > 1, which it will always be, since you never decrease the value of i. I think you meant to use jsTime in the conditional instead. Renaming it to something that gives it some context may make it easier to follow. Ex remainingTimeSeconds. See the revised code below.
let div = document.getElementById("div");
let score = document.querySelector("h3");
let time = document.querySelector("span");
var jsTime = 60;
var jsScore = 0;
alert("Click inside the box as many times as you can in one minute. \n Ready?");
var clicker = div.addEventListener("click", function() {
jsScore++;
score.innerHTML = jsScore;
},1);
setInterval(function() {
// As long as there is time left, keep decreasing it, and update the time element's innerHTML with the new current time.
if (jsTime > 1){
jsTime--;
time.innerHTML = jsTime;
} else {
removeEventListener(clicker);
}
},1000);

Button text transition with pure Javascript

I have a fade in function made with pure javascript as this site shows.
function fadeIn(el) {
var opacity = 0;
el.style.opacity = 0;
el.style.filter = '';
var last = +new Date();
var tick = function() {
opacity += (new Date() - last) / 400;
el.style.opacity = opacity;
el.style.filter = 'alpha(opacity=' + (100 * opacity)|0 + ')';
last = +new Date();
if (opacity < 1) {
(window.requestAnimationFrame && requestAnimationFrame(tick)) || setTimeout(tick, 16);
}
};
tick();
}
What I need is to apply this transition in a change of button text, something like:
var firstChild = document.getElementById('my-button').firstChild;
firstChild.data = 'Another text';
fadeIn(firstChild);
Of course this do not works as expected, but I wanted something to achieve a behavior that on a change text, a fade in transition is triggered only to the text, not to the entire button.
Is there a way to achieve this?
Since you're using firstChild i assume your text is inside a child element of the button element, if that is the case, this will work.
Click the blue "run code snippet" button at the bottom to see it in action.
btn.addEventListener('click', function(){fadeOut(this.firstChild, newText)});
var newText = "World!";
function fadeOut(e, nT) {
o=1;
t=setInterval(function () {
if(o <= 0.1){
clearInterval(t);
e.style.filter = "alpha(opacity=0)";
if(nT != undefined) {
e.innerHTML = nT;
fadeIn(e);
}
}
e.style.opacity = o;
e.style.filter = 'alpha(opacity='+o*100+")";
o-=o*0.05;
}, 10);
}
function fadeIn(e) {
o=0;
t=setInterval(function () {
if(o >= 0.9){
clearInterval(t);
e.style.filter = "alpha(opacity=1)";
}
e.style.opacity = o;
e.style.filter = 'alpha(opacity='+o*100+")";
o+=0.05;
}, 25);
}
#btn {
color: Black;
width: 100px;
border: 1px solid black;
}
<button id="btn"><p>hello</p></button>
To change the text colour, using this function, you can set it's colour using RGBA - the A stands for the alpha channel.
So, something like this:
el.style.color = "rgba(0,0,0, "+ OPACITY +")" // Opacity is 0 - 1
You could also make your code more modular, allowing you to edit any style property with this fade function.
function fadeIn(el,prop,color) {
var opacity = 0;
el.style[prop] = 0;
var last = +new Date();
var tick = function() {
opacity += (new Date() - last) / 400;
el.style[prop] = "rgba("+color+","+opacity+")";
last = +new Date();
if (opacity < 1) {
(window.requestAnimationFrame && requestAnimationFrame(tick)) || setTimeout(tick, 16);
}
};
tick();
}
now you could do both:
fadeIn(firstChild,"background", "255,0,0"); // fade in background to red
fadeIn(firstChild,"color", "0,0,0"); // fade in text to black

How to set up "stop" after setInterval() method?

i have image gallery ant i set up setinterval, now i want that it should be stopped after two or tree circle.
This is my html Code:
<div id="slider">
<img src="http://imgsrc.hubblesite.org/hu/gallery/db/spacecraft/24/formats/24_web.jpg">
<img src="http://imgsrc.hubblesite.org/hu/gallery/db/spacecraft/27/formats/27_web.jpg">
<img src="http://imgsrc.hubblesite.org/hu/gallery/db/spacecraft/32/formats/32_web.jpg">
<img src="http://imgsrc.hubblesite.org/hu/gallery/db/spacecraft/33/formats/33_web.jpg">
</div>
css:
#slider {
width: 400px;
height: 300px;
position: relative;
overflow: hidden
}
#slider img {
position: absolute;
top: 0;
left: 0;
opacity: 0;
transition: 0.25s
}
and Javascript:
var pics;
var current = 0; // first next() moves to pics[0], the first image
window.addEventListener("load", function() {
pics = document.querySelectorAll("#slider img");
});
setInterval(function() {
var nextImage = (current + 1) % pics.length;
pics[current].style.opacity = 0;
pics[nextImage].style.opacity = 1;
current = nextImage;
}, 3000);
Here's your answer: Stop setInterval call in JavaScript
Save the interval ID when you create it, keep track of the number of times your slides have rotated, and then cancel the interval.
Use a counter variable to track the number of cycles & clear the timer based on that limit value.
JS Code:
var counter = 0;
var limit = 3 ;
var timer;
timer =setInterval(function () {
if(counter === 3){
clearInterval(timer);
return;
}
counter++;
//do some stuff here after 1 second delay
},1000);
You could use setTimeout instead.
var pics;
var current = 0; // first next() moves to pics[0], the first image
var stop = 3; //define when you want to stop
window.addEventListener("load", function() {
pics = document.querySelectorAll("#slider img");
});
function switchImage()
{
var nextImage = (current + 1) % pics.length;
pics[current].style.opacity = 0;
pics[nextImage].style.opacity = 1;
current = nextImage;
stop--;
if(stop != 0)
setTimeout(switchImage,3000);
}
setTimeout(switchImage,3000);
You can do like this.
var refreshIntervalId = setInterval(function() {
var nextImage = (current + 1) % pics.length;
pics[current].style.opacity = 0;
pics[nextImage].style.opacity = 1;
current = nextImage;
}, 3000);
clearInterval(refreshIntervalId);

Javascript div fade in not working using setInterval

I'm trying to make a div containing a number of pictures to fade in but its not working and I don't know why. I believe that the inverval is not even being called. The div's opacity is set to 0.0 This is the code:
var movies = getElementById("movies");
var apparence = function(){
if(movies.style.opacity < 1.0){
movies.style.opacity = movies.style.opacity + 0.1;
} else { clearInterval(timer);
}
}
var timer = window.setInterval(apparence, 1000);
Thank you very much.
To set your movies var, you need to call:
document.getElementById('movies');
The way you are attempting to increment opacity didn't work, so I've updated your example.
New Code:
var movies = document.getElementById("movies");
var opacity = 0.1;
var apparence = function(){
if(opacity <= 1.0) {
movies.style.opacity = opacity;
} else {
clearInterval(timer);
}
opacity += 0.1;
}
var timer = window.setInterval(apparence, 1000);
JS Fiddle:
http://jsfiddle.net/onov6cq4/1/
Here is your problem
Problem1:
If you have defined your css using
#movies {
opacity: 0.0;
}
then document.getElementById().style.opacity is empty since it takes from inline style i.e. <div id="movies" style="opacity: 0.0">
Problem 2:
movies.style.opacity = movies.style.opacity + 0.1;
movies.style.opacity returns a string so you are basically appending string which results in 0.10.1 and so on. You need to do parseFloat! The attached fiddle will solve your problem
Code:
var moviesOp = document.getElementById('movies').style.opacity;
function apparence(){
console.log('interval called with op = ' + moviesOp);
if(moviesOp < 1.0){
moviesOp = parseFloat(moviesOp, 10) + 0.1;
} else {
clearInterval(timer);
}
}
var timer = setInterval(apparence, 1000);
<div id="movies" style="opacity: 0.0">
JSBin With Inline Style
If you want to use in css and not inline then use getComputedStyle. This i tried and works as u wanted
var movies = document.getElementById('movies');
function apparence(){
var moviesOp = getComputedStyle(movies).getPropertyValue('opacity');
console.log('interval called with op = ' + moviesOp);
if(moviesOp < 1.0){
movies.style.opacity = parseFloat(moviesOp, 10) + 0.1;
} else {
clearInterval(timer);
}
}
var timer = setInterval(apparence, 1000);
Non Inline jsBin

How to do fade-in and fade-out with JavaScript and CSS

I want to make an HTML div tag fade in and fade out.
I have some code that fades out, but when I fade in, the opacity of the div stays at 0.1 and doesn't increase.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
<title>Fade to Black</title>
<script type="text/javascript">
//<![CDATA[
function slidePanel(elementToSlide, slideSource)
{
var element = document.getElementById(elementToSlide);
if(element.up == null || element.up == false) {
setTimeout("fadeOut(\"" + elementToSlide + "\")", 100);
element.up = true;
slideSource.innerHTML = "Bring it down";
} else {
setTimeout("fadeIn(\"" + elementToSlide + "\")", 100);
element.up = false;
slideSource.innerHTML = "Take it up";
}
}
function fadeIn(elementToFade)
{
var element = document.getElementById(elementToFade);
element.style.opacity += 0.1;
if(element.style.opacity > 1.0) {
element.style.opacity = 1.0;
} else {
setTimeout("fadeIn(\"" + elementToFade + "\")", 100);
}
}
function fadeOut(elementToFade)
{
var element = document.getElementById(elementToFade);
element.style.opacity -= 0.1;
if(element.style.opacity < 0.0) {
element.style.opacity = 0.0;
} else {
setTimeout("fadeOut(\"" + elementToFade + "\")", 100);
}
}
//]]>
</script>
</head>
<body>
<div>
<div id="slideSource"
style="width:150px; height:20px;
text-align:center; background:green"
onclick="slidePanel('panel', this)">
Take It up
</div>
<div id="panel"
style="width:150px; height:130px;
text-align:center; background:red;
opacity:1.0;">
Contents
</div>
</div>
</body>
</html>
What am I doing wrong and what is the best way to fade in and fade out an element?
Here is a more efficient way of fading out an element:
function fade(element) {
var op = 1; // initial opacity
var timer = setInterval(function () {
if (op <= 0.1){
clearInterval(timer);
element.style.display = 'none';
}
element.style.opacity = op;
element.style.filter = 'alpha(opacity=' + op * 100 + ")";
op -= op * 0.1;
}, 50);
}
you can do the reverse for fade in
setInterval or setTimeout should not get a string as argument
google the evils of eval to know why
And here is a more efficient way of fading in an element.
function unfade(element) {
var op = 0.1; // initial opacity
element.style.display = 'block';
var timer = setInterval(function () {
if (op >= 1){
clearInterval(timer);
}
element.style.opacity = op;
element.style.filter = 'alpha(opacity=' + op * 100 + ")";
op += op * 0.1;
}, 10);
}
Here is a simplified running example of Seattle Ninja's solution.
var slideSource = document.getElementById('slideSource');
document.getElementById('handle').onclick = function () {
slideSource.classList.toggle('fade');
}
#slideSource {
opacity: 1;
transition: opacity 1s;
}
#slideSource.fade {
opacity: 0;
}
<button id="handle">Fade</button>
<div id="slideSource">Whatever you want here - images or text</div>
why do that to yourself?
jQuery:
$("#element").fadeOut();
$("#element").fadeIn();
I think that's easier.
www.jquery.com
Here's my attempt with Javascript and CSS3 animation
So the HTML:
<div id="handle">Fade</div>
<div id="slideSource">Whatever you want images or text here</div>
The CSS3 with transitions:
div#slideSource {
opacity:1;
-webkit-transition: opacity 3s;
-moz-transition: opacity 3s;
transition: opacity 3s;
}
div#slideSource.fade {
opacity:0;
}
The Javascript part. Check if the className exists, if it does then add the class and transitions.
document.getElementById('handle').onclick = function(){
if(slideSource.className){
document.getElementById('slideSource').className = '';
} else {
document.getElementById('slideSource').className = 'fade';
}
}
Just click and it will fade in and out. I would recommend using JQuery as Itai Sagi mentioned. I left out Opera and MS, so I would recommend using prefixr to add that in the css. This is my first time posting on stackoverflow but it should work fine.
Ok, I've worked it out
element.style.opacity = parseFloat(element.style.opacity) + 0.1;
Should be used instead of
element.style.opacity += 0.1;
Same with
element.style.opacity = parseFloat(element.style.opacity) - 0.1;
Instead of
element.style.opacity -= 0.1;
Because opacity value is stored as string, not as float. I'm still not sure though why the addition has worked.
I usually use these utility functions. element is the HTML element and duration is the desired duration in milliseconds.
export const fadeIn = (element, duration) => {
(function increment(value = 0) {
element.style.opacity = String(value);
if (element.style.opacity !== '1') {
setTimeout(() => {
increment(value + 0.1);
}, duration / 10);
}
})();
};
export const fadeOut = (element, duration) => {
(function decrement() {
(element.style.opacity -= 0.1) < 0 ? element.style.display = 'none' : setTimeout(() => {
decrement();
}, duration / 10);
})();
};
Heres my code for a fade in/out toggle functions.
fadeIn: function (len) {
var obj = this.e;
obj.style.display = '';
var op = 0;
var timer = setInterval(function () {
if (op >= 1 || op >= 1.0){
console.log('done', op)
clearInterval(timer);
}
obj.style.opacity = op.toFixed(1);
op += 0.1;
console.log(obj.style.opacity);
}, len);
return this;
},
fadeOut: function (len) {
var obj = this.e;
var op = 1;
var timer = setInterval(function () {
if (op <= 0){
clearInterval(timer);
console.log('done', op)
obj.style.display = 'none';
}
obj.style.opacity = op.toFixed(1);
op -= 0.1;
console.log(obj.style.opacity)
}, len);
return this;
},
This was from a jQuery style lib i did. hope it's helpfull. link to lib on cloud9:
https://c9.io/christopherdumas/magik_wb
I like Ibu's one but, I think I have a better solution using his idea.
//Fade In.
element.style.opacity = 0;
var Op1 = 0;
var Op2 = 1;
var foo1, foo2;
foo1 = setInterval(Timer1, 20);
function Timer1()
{
element.style.opacity = Op1;
Op1 = Op1 + .01;
console.log(Op1); //Option, but I recommend it for testing purposes.
if (Op1 > 1)
{
clearInterval(foo1);
foo2 = setInterval(Timer3, 20);
}
}
This solution uses a additional equation unlike Ibu's solution, which used a multiplicative equation. The way it works is it takes a time increment (t), an opacity increment (o), and a opacity limit (l) in the equation, which is: (T = time of fade in miliseconds) [T = (l/o)*t]. the "20" represents the time increments or intervals (t), the ".01" represents the opacity increments (o), and the 1 represents the opacity limit (l). When you plug the numbers in the equation you get 2000 milliseconds (or 2 seconds). Here is the console log:
0.01
0.02
0.03
0.04
0.05
0.060000000000000005
0.07
0.08
0.09
0.09999999999999999
0.10999999999999999
0.11999999999999998
0.12999999999999998
0.13999999999999999
0.15
0.16
0.17
0.18000000000000002
0.19000000000000003
0.20000000000000004
0.21000000000000005
0.22000000000000006
0.23000000000000007
0.24000000000000007
0.25000000000000006
0.26000000000000006
0.2700000000000001
0.2800000000000001
0.2900000000000001
0.3000000000000001
0.3100000000000001
0.3200000000000001
0.3300000000000001
0.34000000000000014
0.35000000000000014
0.36000000000000015
0.37000000000000016
0.38000000000000017
0.3900000000000002
0.4000000000000002
0.4100000000000002
0.4200000000000002
0.4300000000000002
0.4400000000000002
0.45000000000000023
0.46000000000000024
0.47000000000000025
0.48000000000000026
0.49000000000000027
0.5000000000000002
0.5100000000000002
0.5200000000000002
0.5300000000000002
0.5400000000000003
0.5500000000000003
0.5600000000000003
0.5700000000000003
0.5800000000000003
0.5900000000000003
0.6000000000000003
0.6100000000000003
0.6200000000000003
0.6300000000000003
0.6400000000000003
0.6500000000000004
0.6600000000000004
0.6700000000000004
0.6800000000000004
0.6900000000000004
0.7000000000000004
0.7100000000000004
0.7200000000000004
0.7300000000000004
0.7400000000000004
0.7500000000000004
0.7600000000000005
0.7700000000000005
0.7800000000000005
0.7900000000000005
0.8000000000000005
0.8100000000000005
0.8200000000000005
0.8300000000000005
0.8400000000000005
0.8500000000000005
0.8600000000000005
0.8700000000000006
0.8800000000000006
0.8900000000000006
0.9000000000000006
0.9100000000000006
0.9200000000000006
0.9300000000000006
0.9400000000000006
0.9500000000000006
0.9600000000000006
0.9700000000000006
0.9800000000000006
0.9900000000000007
1.0000000000000007
1.0100000000000007
Notice how the opacity follows the opacity increment amount of .01 just like in the code. If you use the code Ibu made,
//I made slight edits but keeped the ESSENTIAL stuff in it.
var op = 0.01; // initial opacity
var timer = setInterval(function () {
if (op >= 1){
clearInterval(timer);
}
element.style.opacity = op;
op += op * 0.1;
}, 20);
you will get these numbers (or something similar) in you console log. Here is what I got.
0.0101
0.010201
0.01030301
0.0104060401
0.010510100501
0.010615201506009999
0.0107213535210701
0.0108285670562808
0.010936852726843608
0.011046221254112044
0.011156683466653165
0.011268250301319695
0.011380932804332892
0.01149474213237622
0.011609689553699983
0.011725786449236983
0.011843044313729352
0.011961474756866645
0.012081089504435313
0.012201900399479666
0.012323919403474463
0.012447158597509207
0.0125716301834843
0.012697346485319142
0.012824319950172334
0.012952563149674056
0.013082088781170797
0.013212909668982505
0.01334503876567233
0.013478489153329052
0.013613274044862343
0.013749406785310966
0.013886900853164076
0.014025769861695717
0.014166027560312674
0.014307687835915801
0.01445076471427496
0.01459527236141771
0.014741225085031886
0.014888637335882205
0.015037523709241028
0.015187898946333437
0.01533977793579677
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Notice that there is no discernible pattern. If you ran Ibu's code, you would never know how long the fade was. You would have to grab a timer and guess and check 2 seconds. Nonetheless, Ibu's code did make a pretty nice fade in (it probably works for fade out. I don't know because I didn't use a fade out yet). My code will also work for a fade out. Let's just say you wanted 2 seconds for a fade out. You can do that with my code. Here is how it would look:
//Fade out. (Continued from the fade in.
function Timer2()
{
element.style.opacity = Op2;
Op2 = Op2 - .01;
console.log(Op2); //Option, but I recommend it for testing purposes.
if (Op2 < 0)
{
clearInterval(foo2);
}
}
All I did was change the opacity to 1 (or fully opaque). I changed the opacity increment to -.01 so it would start turning invisible. Lastly, I changed the opacity limit to 0. When it hits the opacity limit, the timer will stop. Same as the last one, except it used 1 instead of 0. When you run the code, here is what the console log should relatively look like.
.99
0.98
0.97
0.96
0.95
0.94
0.9299999999999999
0.9199999999999999
0.9099999999999999
0.8999999999999999
0.8899999999999999
0.8799999999999999
0.8699999999999999
0.8599999999999999
0.8499999999999999
0.8399999999999999
0.8299999999999998
0.8199999999999998
0.8099999999999998
0.7999999999999998
0.7899999999999998
0.7799999999999998
0.7699999999999998
0.7599999999999998
0.7499999999999998
0.7399999999999998
0.7299999999999998
0.7199999999999998
0.7099999999999997
0.6999999999999997
0.6899999999999997
0.6799999999999997
0.6699999999999997
0.6599999999999997
0.6499999999999997
0.6399999999999997
0.6299999999999997
0.6199999999999997
0.6099999999999997
0.5999999999999996
0.5899999999999996
0.5799999999999996
0.5699999999999996
0.5599999999999996
0.5499999999999996
0.5399999999999996
0.5299999999999996
0.5199999999999996
0.5099999999999996
0.49999999999999956
0.48999999999999955
0.47999999999999954
0.46999999999999953
0.4599999999999995
0.4499999999999995
0.4399999999999995
0.4299999999999995
0.4199999999999995
0.4099999999999995
0.39999999999999947
0.38999999999999946
0.37999999999999945
0.36999999999999944
0.35999999999999943
0.3499999999999994
0.3399999999999994
0.3299999999999994
0.3199999999999994
0.3099999999999994
0.2999999999999994
0.28999999999999937
0.27999999999999936
0.26999999999999935
0.25999999999999934
0.24999999999999933
0.23999999999999932
0.22999999999999932
0.2199999999999993
0.2099999999999993
0.1999999999999993
0.18999999999999928
0.17999999999999927
0.16999999999999926
0.15999999999999925
0.14999999999999925
0.13999999999999924
0.12999999999999923
0.11999999999999923
0.10999999999999924
0.09999999999999924
0.08999999999999925
0.07999999999999925
0.06999999999999926
0.059999999999999255
0.04999999999999925
0.03999999999999925
0.02999999999999925
0.019999999999999248
0.009999999999999247
-7.528699885739343e-16
-0.010000000000000753
As you can see, the .01 pattern still exists in the fade out. Both fades are smooth and precise. I hope these codes helped you or gave you insight on the topic. If you have any additions or suggestions let me know. Thank you for taking the time to view this!
I think i get the problem :
Once you make the div fade out you aren't exiting the function : fadeout calls itself again over even after opacity has become 0
if(element.style.opacity < 0.0) {
return;
}
And do the same for fadein too
let count=0;
let text = document.getElementById('heading');
let btn = document.getElementById('btn');
btn.addEventListener('click', function(){
if(count%2==0){
text.style.opacity="0.1";
unfade(text);
text.innerText="Welcome to Javascript </>";
text.style.color="forestgreen";
}//end of if
else{ text.style.opacity="0.1";
unfade(text);
text.innerText="Hello javascript";
text.style.color="blueviolet";
}//end of else
count++;//for toggling the text
});
//function for fade effect--------
function unfade(element) {
var op = 0.1; // initial opacity
element.style.display = 'block';
var timer = setInterval(function () {
if (op >= 1){
clearInterval(timer);
}
element.style.opacity = op;
element.style.filter = 'alpha(opacity=' + op * 100 + ")";
op += op * 0.1;
}, 30);
}
<h1 style="color:blueviolet" id="heading">Hello javascript</h1>
<button id="btn">Click me</button>
The following javascript will fade in an element from opacity 0 to whatever the opacity value was at the time of calling fade in. You can also set the duration of the animation which is nice:
function fadeIn(element) {
var duration = 0.5;
var interval = 10;//ms
var op = 0.0;
var iop = element.style.opacity;
var timer = setInterval(function () {
if (op >= iop) {
op = iop;
clearInterval(timer);
}
element.style.opacity = op;
op += iop/((1000/interval)*duration);
}, interval);
}
*Based on IBUs answer but modified to account for previous opacity value and ability to set duration, also removed irrelevant CSS changes it was making
My answer is based on Gb01's answer (thank you!). I wanted to abstract out the logic so that we could simply pass an element to a function and have that element fade toggle, fade in, or fade out.
POD
To use the code below:
Elements that can be faded should be given the fadeable class.
Fade in/out with fadeInElement(element) and fadeOutElement(element).
Turn fade on/off with toggle, toggleElementFade(element).
Improvements Over Gb01's answer
Bug Fix: Gb01's answer only worked because id-based CSS rules take precedence over class-based CSS rules, and if you removed #slideSource from #slideSource.fade, it would cease to work.
Bug Fix: Gb01's answer provides for when you start with the element displayed. What if you want to start with it hidden? Completely different code is required
Code: Elements Begin Being Displayed
function fadeInElement(element) {
element.classList.remove('fade');
}
function fadeOutElement(element) {
element.classList.add('fade');
}
function toggleElementFade(element) {
element.classList.toggle('fade');
}
document.getElementById('fade-toggle').onclick = function () {
toggleElementFade(document.getElementsByClassName('fadeable')[0]);
}
document.getElementById('fade-in').onclick = function () {
fadeInElement(document.getElementsByClassName('fadeable')[0]);
}
document.getElementById('fade-out').onclick = function () {
fadeOutElement(document.getElementsByClassName('fadeable')[0]);
}
.fadeable {
opacity: 1;
transition: opacity 1s;
}
.fade {
opacity: 0 !important;
}
<button id="fade-toggle">Fade Toggle</button>
<button id="fade-in">Fade In</button>
<button id="fade-out">Fade Out</button>
<div class="fadeable">Whatever you want here - images or text</div>
Code: Elements Begin Being Hidden
function fadeInElement(element) {
element.style.removeProperty('display');
setTimeout(function() {
element.classList.remove('fade');
}, 10);
}
function fadeOutElement(element) {
element.classList.add('fade');
}
function toggleElementFade(element) {
element.style.removeProperty('display');
setTimeout(function() {
element.classList.toggle('fade');
}, 10);
}
document.getElementById('fade-toggle').onclick = function () {
toggleElementFade(document.getElementsByClassName('fadeable')[0]);
}
document.getElementById('fade-in').onclick = function () {
fadeInElement(document.getElementsByClassName('fadeable')[0]);
}
document.getElementById('fade-out').onclick = function () {
fadeOutElement(document.getElementsByClassName('fadeable')[0]);
}
.fadeable {
opacity: 1;
transition: opacity 1s;
}
.fade {
opacity: 0 !important;
}
<button id="fade-toggle">Fade Toggle</button>
<button id="fade-in">Fade In</button>
<button id="fade-out">Fade Out</button>
<div class="fadeable fade" style="display:none;">Whatever you want here - images or text</div>
That was actually quite simple .
for ex: if you are hiding the text or changing it's color .
document.getElementById('availabletoday').style.color = '#f4f6f7';
make a css property like this
#availabletoday{
transition: 1s;
}
depending upon your event listener when the JavaScript executes it will transition in 1s . really easy to change the delay .
Let me know if this helps

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