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This question already has answers here:
How to add my own methods to HTMLElement object?
(5 answers)
Closed 4 years ago.
I'm trying to create a similar function to the jquery .fadeOut() effect in pure javascript, but I'm having trouble with my code. The error code:
span[0].fadeOutEffect is not a function
My code:
var span = document.querySelectorAll("span");
function fadeOutEffect() {
var node = this
var fadeEffect = setInterval(function() {
if (!node.style.opacity) {
node.style.opacity = 1;
}
if (node.style.opacity > 0) {
node.style.opacity -= 0.1;
} else {
clearInterval(fadeEffect);
}
}, 50);
}
span[0].fadeOutEffect();
<span>one </span><span>two </span><span>three </span>
When I read your code, I see you likely want to add a function to the HTMLElement prototype - it is not recommended but it will look like this:
HTMLElement.prototype.fadeOutEffect = function() {
var node = this
var fadeEffect = setInterval(function() {
if (!node.style.opacity) {
node.style.opacity = 1;
}
if (node.style.opacity > 0) {
node.style.opacity -= 0.1;
} else {
clearInterval(fadeEffect);
}
}, 50);
}
var span = document.querySelectorAll("span");
span[0].fadeOutEffect();
<span>one </span><span>two </span><span>three </span>
A cleaner way is passing the span:
var fadeOutEffect = function(node) {
var fadeEffect = setInterval(function() {
if (!node.style.opacity) {
node.style.opacity = 1;
}
if (node.style.opacity > 0) {
node.style.opacity -= 0.1;
} else {
clearInterval(fadeEffect);
}
}, 50);
}
var span = document.querySelectorAll("span");
fadeOutEffect(span[0]);
<span>one </span><span>two </span><span>three </span>
You are trying to add a function as a property to the array of span elements. You should instead pass it as a parameter to the function you created. Also, document.querySelectorAll("span"); returns an array of spans, as there can be multiple in your HTML document, so you can loop through each and apply you code to them.
See working example:
function fadeOutEffect(nodes) {
nodes.forEach(function(node) { // Loop through each node (each span) in the array of spans
var fadeEffect = setInterval(function() { // Run your code
if (!node.style.opacity) {
node.style.opacity = 1;
}
if (node.style.opacity > 0) {
node.style.opacity -= 0.1;
} else {
clearInterval(fadeEffect);
}
}, 50);
});
}
var nodes = document.querySelectorAll("span"); // Nodes is an array of spans
fadeOutEffect(nodes); // Pass the array of spans to your function
<span>Hello world!</span>
Your code is attempting to call a function, on a DOM element, which doesn't exist. Try passing the element as a parameter to your function instead.
var span = document.querySelectorAll("span");
function fadeOutEffect(node) {
var fadeEffect = setInterval(function() {
if (!node.style.opacity) {
node.style.opacity = 1;
}
if (node.style.opacity > 0) {
node.style.opacity -= 0.1;
} else {
clearInterval(fadeEffect);
}
}, 50);
}
fadeOutEffect(span[0]);
<span>one </span><span>two </span><span>three </span>
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
0.015493175715154739
0.015648107472306286
0.01580458854702935
0.015962634432499644
0.01612226077682464
0.016283483384592887
0.016446318218438817
0.016610781400623206
0.01677688921462944
0.016944658106775732
0.01711410468784349
0.017285245734721923
0.017458098192069144
0.017632679173989835
0.01780900596572973
0.01798709602538703
0.018166966985640902
0.01834863665549731
0.018532123022052285
0.018717444252272807
0.018904618694795535
0.01909366488174349
0.019284601530560927
0.019477447545866538
0.0196722220213252
0.019868944241538455
0.02006763368395384
0.02026831002079338
0.020470993121001313
0.020675703052211326
0.02088246008273344
0.021091284683560776
0.021302197530396385
0.02151521950570035
0.021730371700757353
0.021947675417764927
0.022167152171942577
0.022388823693662
0.022612711930598623
0.022838839049904608
0.023067227440403654
0.02329789971480769
0.023530878711955767
0.023766187499075324
0.024003849374066077
0.02424388786780674
0.024486326746484807
0.024731190013949654
0.024978501914089152
0.025228286933230044
0.025480569802562344
0.025735375500587968
0.025992729255593847
0.026252656548149785
0.026515183113631283
0.026780334944767597
0.027048138294215273
0.027318619677157426
0.027591805873929
0.02786772393266829
0.028146401171994972
0.028427865183714922
0.02871214383555207
0.02899926527390759
0.029289257926646668
0.029582150505913136
0.029877972010972267
0.030176751731081992
0.030478519248392812
0.03078330444087674
0.031091137485285508
0.031402048860138365
0.03171606934873975
0.03203323004222715
0.03235356234264942
0.03267709796607591
0.03300386894573667
0.03333390763519403
0.03366724671154597
0.03400391917866143
0.03434395837044805
0.03468739795415253
0.03503427193369406
0.035384614653031
0.035738460799561306
0.03609584540755692
0.03645680386163249
0.03682137190024882
0.03718958561925131
0.03756148147544382
0.03793709629019826
0.03831646725310024
0.038699631925631243
0.03908662824488755
0.039477494527336426
0.03987226947260979
0.040270992167335894
0.04067370208900925
0.04108043910989934
0.04149124350099834
0.04190615593600832
0.042325217495368404
0.04274846967032209
0.04317595436702531
0.04360771391069556
0.044043791049802515
0.04448422896030054
0.04492907124990354
0.04537836196240258
0.045832145582026605
0.04629046703784687
0.04675337170822534
0.047220905425307595
0.04769311447956067
0.04817004562435628
0.04865174608059984
0.04913826354140584
0.0496296461768199
0.0501259426385881
0.05062720206497398
0.05113347408562372
0.05164480882647996
0.05216125691474476
0.05268286948389221
0.053209698178731134
0.05374179516051845
0.05427921311212363
0.05482200524324487
0.05537022529567732
0.05592392754863409
0.056483166824120426
0.05704799849236163
0.05761847847728525
0.0581946632620581
0.05877660989467868
0.059364375993625464
0.05995801975356172
0.060557599951097336
0.06116317595060831
0.06177480771011439
0.06239255578721554
0.0630164813450877
0.06364664615853857
0.06428311262012396
0.0649259437463252
0.06557520318378844
0.06623095521562633
0.0668932647677826
0.06756219741546042
0.06823781938961503
0.06892019758351117
0.06960939955934628
0.07030549355493974
0.07100854849048914
0.07171863397539403
0.07243582031514798
0.07316017851829945
0.07389178030348245
0.07463069810651728
0.07537700508758245
0.07613077513845827
0.07689208288984285
0.07766100371874128
0.0784376137559287
0.07922198989348798
0.08001420979242287
0.0808143518903471
0.08162249540925057
0.08243872036334307
0.0832631075669765
0.08409573864264626
0.08493669602907272
0.08578606298936345
0.08664392361925709
0.08751036285544966
0.08838546648400417
0.08926932114884421
0.09016201436033265
0.09106363450393598
0.09197427084897535
0.0928940135574651
0.09382295369303975
0.09476118322997015
0.09570879506226986
0.09666588301289256
0.09763254184302148
0.0986088672614517
0.09959495593406621
0.10059090549340688
0.10159681454834095
0.10261278269382436
0.1036389105207626
0.10467529962597022
0.10572205262222992
0.10677927314845222
0.10784706587993674
0.10892553653873611
0.11001479190412347
0.1111149398231647
0.11222608922139635
0.11334835011361032
0.11448183361474643
0.11562665195089389
0.11678291847040283
0.11795074765510685
0.11913025513165793
0.1203215576829745
0.12152477325980425
0.12274002099240229
0.12396742120232632
0.12520709541434957
0.12645916636849308
0.127723758032178
0.12900099561249978
0.13029100556862477
0.13159391562431103
0.13290985478055414
0.1342389533283597
0.13558134286164328
0.1369371562902597
0.1383065278531623
0.13968959313169393
0.14108648906301088
0.142497353953641
0.1439223274931774
0.14536155076810917
0.14681516627579025
0.14828331793854815
0.14976615111793362
0.15126381262911295
0.15277645075540408
0.15430421526295812
0.1558472574155877
0.15740572998974356
0.158979787289641
0.1605695851625374
0.16217528101416276
0.16379703382430438
0.16543500416254742
0.1670893542041729
0.16876024774621462
0.17044785022367676
0.17215232872591352
0.17387385201317265
0.17561259053330439
0.17736871643863744
0.1791424036030238
0.18093382763905405
0.1827431659154446
0.18457059757459904
0.18641630355034502
0.1882804665858485
0.19016327125170698
0.19206490396422404
0.19398555300386627
0.19592540853390494
0.197884662619244
0.19986350924543644
0.20186214433789082
0.20388076578126973
0.20591957343908243
0.20797876917347324
0.21005855686520797
0.21215914243386005
0.21428073385819865
0.21642354119678064
0.21858777660874845
0.22077365437483593
0.2229813909185843
0.22521120482777013
0.22746331687604782
0.2297379500448083
0.23203532954525638
0.23435568284070896
0.23669923966911605
0.2390662320658072
0.24145689438646528
0.24387146333032994
0.24631017796363325
0.24877327974326957
0.25126101254070227
0.2537736226661093
0.2563113588927704
0.2588744724816981
0.26146321720651505
0.2640778493785802
0.266718627872366
0.26938581415108964
0.27207967229260055
0.27480046901552657
0.27754847370568186
0.28032395844273866
0.28312719802716607
0.28595847000743774
0.2888180547075121
0.2917062352545872
0.2946232976071331
0.2975695305832044
0.3005452258890364
0.3035506781479268
0.3065861849294061
0.3096520467787002
0.3127485672464872
0.31587605291895204
0.31903481344814155
0.322225161582623
0.3254474131984492
0.3287018873304337
0.33198890620373805
0.33530879526577545
0.3386618832184332
0.34204850205061754
0.3454689870711237
0.34892367694183496
0.35241291371125333
0.35593704284836586
0.3594964132768495
0.363091377409618
0.3667222911837142
0.3703895140955513
0.37409340923650686
0.37783434332887195
0.38161268676216065
0.38542881362978226
0.3892831017660801
0.3931759327837409
0.3971076921115783
0.40107876903269407
0.405089556723021
0.4091404522902512
0.4132318568131537
0.41736417538128523
0.4215378171350981
0.42575319530644906
0.43001072725951356
0.43431083453210867
0.43865394287742976
0.4430404823062041
0.44747088712926614
0.4519455960005588
0.45646505196056436
0.46102970248017
0.4656399995049717
0.47029639950002144
0.47499936349502164
0.47974935712997185
0.48454685070127157
0.4893923192082843
0.4942862424003671
0.4992291048243708
0.5042213958726145
0.5092636098313407
0.5143562459296541
0.5194998083889507
0.5246948064728402
0.5299417545375685
0.5352411720829442
0.5405935838037736
0.5459995196418114
0.5514595148382295
0.5569741099866118
0.5625438510864779
0.5681692895973427
0.5738509824933161
0.5795894923182493
0.5853853872414317
0.5912392411138461
0.5971516335249846
0.6031231498602344
0.6091543813588367
0.615245925172425
0.6213983844241493
0.6276123682683908
0.6338884919510748
0.6402273768705855
0.6466296506392913
0.6530959471456843
0.6596269066171412
0.6662231756833126
0.6728854074401457
0.6796142615145472
0.6864104041296927
0.6932745081709896
0.7002072532526995
0.7072093257852266
0.7142814190430788
0.7214242332335097
0.7286384755658448
0.7359248603215033
0.7432841089247183
0.7507169500139654
0.7582241195141051
0.7658063607092461
0.7734644243163386
0.7811990685595019
0.789011059245097
0.7969011698375479
0.8048701815359234
0.8129188833512826
0.8210480721847955
0.8292585529066434
0.8375511384357098
0.8459266498200669
0.8543859163182677
0.8629297754814503
0.8715590732362648
0.8802746639686274
0.8890774106083137
0.8979681847143969
0.9069478665615408
0.9160173452271562
0.9251775186794278
0.9344292938662221
0.9437735868048843
0.9532113226729332
0.9627434358996625
0.9723708702586591
0.9820945789612456
0.9919155247508581
1.0018346799983666
1.0118530267983503
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
Basically I have this code that hooks onto a certain element in the website and overrides it's content. In this example it's overriding existing text to make it change every so often. However when it cycles through the preset text lines it simply jumps without an animation. Is it possible to add a fade animation between the preset texts?
Here is the code:
var text = ["Question Everything!", "Envision the future!", "Change your perspective!"];
var counter = 0;
var elem = document.getElementById("slogantxt");
setInterval(change, 3500);
function change() {
elem.innerHTML = text[counter];
counter++;
if(counter >= text.length) { counter = 0; }
}
CSS3 #keyframes animations would be much lighter weight here.
#keyframes fadeOutIn {
0% {opacity: 1;}
50% {opacity: 0;}
100% {opacity: 1;}
}
.fadeOutIn {
animation-name: fadeOutIn;
animation-duration: 200ms;
}
And then simply remove and re-add the class when changing the inner HTML.
EDIT: for simplicity, I left out the necessary -webkit- prefixes. Don't forget!
With JS you can do like below
var text = ["Question Everything!", "Envision the future!", "Change your perspective!"];
var counter = 0;
var elem = document.getElementById("slogantxt");
setInterval(change, 3500);
function change() {
fade(elem,function(){
elem.innerHTML = text[counter];
unfade(elem);
});
counter++;
if(counter >= text.length) { counter = 0; }
}
function fade(element,cbk) {
var op = 1; // initial opacity
var timer = setInterval(function () {
if (op <= 0.1){
clearInterval(timer);
element.style.display = 'none';
cbk();
}
element.style.opacity = op;
element.style.filter = 'alpha(opacity=' + op * 100 + ")";
op -= op * 0.1;
}, 50);
}
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);
}
Ref: How to do fade-in and fade-out with JavaScript and CSS
With jQuery you could do something like this:
$(document).ready(function(){
var text = ["Question Everything!", "Envision the future!", "Change your perspective!"];
var counter = 0;
setInterval(change, 3500);
function change() {
$("#slogantxt").fadeOut('fast',function(){//fade out the element
$(this).html(text[counter]).fadeIn('fast');//once fade out completes, change the element text and fade it back in
});
counter++;
if(counter >= text.length) { counter = 0; }
}
});
Hi friends i want to fade in a div when i click on another div and for that i am using following code. Code1 works fine but i require to use the Code2.
I know there is jQuery but i require to do this in JavaScript
Can you guide me that what kind of mistake i am doing or what i need change...
Code1 --- Works Fine
function starter() { fin(); }
function fin()
{
for (i = 0; i <= 1; i += 0.01)
{
i=Math.round(i*100)/100;
setTimeout("seto(" + i + ")", i * 1000);
}
}
function seto(opa)
{
var ele = document.getElementById("div1");
ele.style.opacity = opa;
}
Code2 --- Does not work
function starter()
{
var ele = document.getElementById("div1");
fin(ele);
}
function fin(ele)
{
for (i = 0; i <= 1; i += 0.01)
{
i=Math.round(i*100)/100;
setTimeout("seto(" + ele + "," + i + ")", i * 1000);
}
}
function seto(ele,opa)
{
ele.style.opacity = opa;
}
Based on this site
EDIT-1
Added the functionality so that user can specify the animation duration(#Marzian comment)
You can try this:
function fadeIn(el, time) {
el.style.opacity = 0;
var last = +new Date();
var tick = function() {
el.style.opacity = +el.style.opacity + (new Date() - last) / time;
last = +new Date();
if (+el.style.opacity < 1) {
(window.requestAnimationFrame && requestAnimationFrame(tick)) || setTimeout(tick, 16);
}
};
tick();
}
var el = document.getElementById("div1");
fadeIn(el, 3000); //first argument is the element and second the animation duration in ms
DEMO
Update:
It seems that people enjoy my minimalistic and elegant approach, Updated for 2022:
No need for complex mechanisms. Just use CSS, which has it out of the box and has better performance overall.
Basically you achieve it with CSS by setting a transition for the opacity. In JavaScript that would be:
const div = document.querySelector('#my-div');
div.style.transition='opacity 1s';
and as a trigger you just set opacity to 0:
div.style.opacity=0;
This will create a 1 second fade out effect and you can use the trigger anywhere. The inverse can also be done to achieve a fade in effect.
Here's a working example:
const div = document.querySelector('#my-div');
div.style.transition='opacity 1s';
// set opacity to 0 -> fade out
setInterval(() => div.style.opacity=0, 1000);
// set opacity to 1 -> fade in
setInterval(() => div.style.opacity=1, 2000);
#my-div { background-color:#FF0000; width:100%; height:100%; padding: 10px; color: #FFF; }
<div id="my-div">Hello!</div>
Seems like your attempting to convert your element, to a string. Try this instead
function starter()
{
var ele = document.getElementById("div1");
fin(ele);
}
function fin(ele)
{
for (i = 0; i <= 1; i += 0.01)
{
i=Math.round(i*100)/100;
setTimeout(function() { setto(ele,i); }, i * 1000);
}
}
function seto(ele,opa)
{
ele.style.opacity = opa;
}
What happens here is, that i call a anonnymous function when the timer hits, and from that function, execute my functioncall to setto.
Hope it helps.
Jonas
The problem here is you are using the pass-a-string method of using setTimeout. Which is basically just a hidden eval.
It's worth noting that this is a bad practice, slow performer, and security risk.
(see questions such as this: setTimeout() with string or (anonymous) function reference? speedwise)
The reason this is causing your problem is because "seto(" + ele + "," + i + ")" is going to evaluate to "seto('[object HTMLDivElement]', 1)". You really want to pass reference to the ele object -- but the value's being cast to a string when you tried concatenating an object onto a string. You can get around this by using the pass-a-function method of using setTImeout.
setTimeout(function() { seto(ele, i); }, i * 1000);
I believe making this change will make your Code2 behavior equivalent to Code1.
Below are the complete answers to my question
ANS1 --- DEMO
function fin() {
var i = 0;
var el = document.getElementById("div1");
fadeIn(el,i);
}
function fadeIn(el,i) {
i = i + 0.01;
seto(el,i);
if (i<1){setTimeout(function(){fadeIn(el,i);}, 10);}
}
function seto(el,i) {
el.style.opacity = i;
}
ANS2 --- DEMO
function fin(){
var i = 0;
var el = document.getElementById("div1");
fadeIn(el,i);
}
function fadeIn(el,i) {
var go = function(i) {
setTimeout( function(){ seto(el,i); } , i * 1000);
};
for ( i = 0 ; i<=1 ; i = i + 0.01) go(i);
}
function seto(el,i)
{
el.style.opacity = i;
}
My version
function fadeIn($element){
$element.style.display="block";
$element.style.opacity=0;
recurseWithDelayUp($element,0,1);
}
function fadeOut($element){
$element.style.display="block";
$element.style.opacity=1;
recurseWithDelayDown($element,1,0);
}
function recurseWithDelayDown($element,startFrom,stopAt){
window.setTimeout(function(){
if(startFrom > stopAt ){
startFrom=startFrom - 0.1;
recurseWithDelayDown($element,startFrom,stopAt)
$element.style.opacity=startFrom;
}else{
$element.style.display="none"
}
},30);
}
function recurseWithDelayUp($element,startFrom,stopAt){
window.setTimeout(function(){
if(startFrom < stopAt ){
startFrom=startFrom + 0.1;
recurseWithDelayUp($element,startFrom,stopAt)
$element.style.opacity=startFrom;
}else{
$element.style.display="block"
}
},30);
}
function hide(fn){
var hideEle = document.getElementById('myElement');
hideEle.style.opacity = 1;
var fadeEffect = setInterval(function() {
if (hideEle.style.opacity < 0.1)
{
hideEle.style.display='none';
fn();
clearInterval(fadeEffect);
}
else
{
hideEle.style.opacity -= 0.1;
}
}, 20);
}
function show(){
var showEle = document.getElementById('myElement');
showEle.style.opacity = 0;
showEle.style.display='block';
var i = 0;
fadeIn(showEle,i);
function fadeIn(showEle,i) {
i = i + 0.05;
seto(showEle,i);
if (i<1){setTimeout(function(){fadeIn(showEle,i);}, 25);}
}
function seto(el,i)
{
el.style.opacity = i;
}
}
hide(show);
I just improved on laaposto's answer to include a callback.
I also added a fade_out function.
It could be made more efficient, but it works great for what i'm doing.
Look at laaposto's answer for implementation instructions.
You can replace the JS in his fiddle with mine and see the example.
Thanks laaposto!
This really helped out for my project that requires zero dependencies.
let el = document.getElementById( "div1" );
function fade_in( element, duration, callback = '' ) {
element.style.opacity = 0;
let last = +new Date();
let tick = function() {
element.style.opacity = +element.style.opacity + ( new Date() - last ) / duration;
last = +new Date();
if ( +element.style.opacity < 1 )
( window.requestAnimationFrame && requestAnimationFrame( tick ) ) || setTimeout( tick, 16 );
else if ( callback !== '' )
callback();
};
tick();
}
function fade_out( element, duration, callback = '' ) {
element.style.opacity = 1;
let last = +new Date();
let tick = function() {
element.style.opacity = +element.style.opacity - ( new Date() - last ) / duration;
last = +new Date();
if ( +element.style.opacity > 0 )
( window.requestAnimationFrame && requestAnimationFrame( tick ) ) || setTimeout( tick, 16 );
else if ( callback !== '' )
callback();
};
tick();
}
fade_out( el, 3000, function(){ fade_in( el, 3000 ) } );
Cheers!
So I've made custom function for a game I'm working on, one being fade in the other one fade out. The problem is fadeOut works, but fading back IN does not... strange. Any clues? See code below.
THIS WORKS:
fadeOut:function(o,duration)
{
o.style.opacity = 1;
o._anim = function()
{
if(o.style.opacity <=0)
{
clearInterval(o._animInt);
return false;
}
o.style.opacity -= .1;
game.log("opacity:" + o.style.opacity);
}
o._animInt = setInterval(o._anim,duration / 10)
}
THIS DOES NOT:
fadeIn:function(o,duration)
{
o.style.opacity = 0;
o._anim = function()
{
if(o.style.opacity >= 1)
{
clearInterval(o._animInt);
return false;
}
o.style.opacity += .1;
game.log("opacity:" + o.style.opacity);
}
o._animInt = setInterval(o._anim,duration / 10)
}
function fadeIn (o,duration) {
o.style.opacity = 0;
o._anim = function() {
var opacity = parseFloat(o.style.opacity);
if(opacity >= 1) { clearInterval(o._animInt); return false;}
o.style.opacity = opacity + 0.1;
game.log("opacity:" + o.style.opacity);
}
o._animInt = setInterval(o._anim,duration / 10)
}
The opacity attribute is a string. Parse it first, compare, increment, then store. This worked for me in Chrome and Firefox.