我想让HTML div标签淡入淡出。
我有一些淡出的代码，但是当我淡入时，div的不透明度保持在0.1并且不会增加。
<!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>
我做错了什么，淡出和淡出元素的最佳方法是什么？
答案 0 :(得分：104)
这是一种更有效的淡出元素的方法：
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);
}
你可以反过来淡出
setInterval或setTimeout不应该将字符串作为参数
谷歌eval的邪恶知道为什么这是一种更有效的淡入元素的方法。
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);
}
答案 1 :(得分：48)
以下是Seattle Ninja's solution的简化运行示例。
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>
答案 2 :(得分：20)
答案 3 :(得分：10)
这是我尝试使用Javascript和CSS3动画 所以HTML：
<div id="handle">Fade</div>
<div id="slideSource">Whatever you want images or text here</div>
带过渡的CSS3：
div#slideSource {
opacity:1;
-webkit-transition: opacity 3s;
-moz-transition: opacity 3s;
transition: opacity 3s;
}
div#slideSource.fade {
opacity:0;
}
Javascript部分。检查className是否存在，如果存在，则添加类和转换。
document.getElementById('handle').onclick = function(){
if(slideSource.className){
document.getElementById('slideSource').className = '';
} else {
document.getElementById('slideSource').className = 'fade';
}
}
只需点击即可淡入淡出。我建议使用JQuery作为Itai Sagi提到的。我遗漏了Opera和MS，所以我建议使用prefixr在css中添加它。这是我第一次在stackoverflow上发帖但它应该可以正常工作。
答案 4 :(得分：8)
好的，我已经解决了
element.style.opacity = parseFloat(element.style.opacity) + 0.1;
应该用来代替
element.style.opacity += 0.1;
与
相同element.style.opacity = parseFloat(element.style.opacity) - 0.1;
而不是
element.style.opacity -= 0.1;
因为不透明度值存储为字符串，而不是float。我仍然不确定为什么添加有效。
答案 5 :(得分：2)
我通常使用这些实用程序功能。 element是HTML元素，duration是所需的持续时间（以毫秒为单位）。
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);
})();
};
答案 6 :(得分：1)
我喜欢Ibu，但我认为我有更好的解决方案。
//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);
}
}
该解决方案使用了一个与Ibu解决方案不同的附加方程，该解决方案使用了乘法方程。它的工作方式是在等式中需要时间增量（t），不透明度增量（o）和不透明度极限（l），即：（T =以毫秒为单位的衰落时间）[T =（l / ○）* T]。 “20”表示时间增量或间隔（t），“。01”表示不透明度增量（o），1表示不透明度极限（l）。当您插入等式中的数字时，您将获得2000毫秒（或2秒）。这是控制台日志：
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
注意不透明度如何遵循.01的不透明度增量，就像在代码中一样。如果您使用Ibu制作的代码，
//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);
您将在控制台日志中获得这些数字（或类似内容）。这就是我得到的。
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
请注意，没有可辨别的模式。如果你运行了Ibu的代码，你永远不会知道淡入淡出的时间。你必须抓住一个计时器并猜测并检查2秒。尽管如此，Ibu的代码确实有一个非常好的淡入淡出（它可能适用于淡出。我不知道因为我还没有使用淡出）。我的代码也适用于淡出。我们只想说你需要2秒才能淡出。你可以用我的代码做到这一点。以下是它的外观：
//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);
}
}
我所做的只是将不透明度更改为1（或完全不透明）。我将不透明度增量更改为-.01，因此它将开始变为不可见。最后，我将不透明度限制更改为0.当它达到不透明度限制时，计时器将停止。与最后一个相同，除了它使用1而不是0.当您运行代码时，控制台日志应该是相对的样子。
.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
正如您所看到的，.01模式仍然存在于淡出中。两种渐变都是平滑而精确的。我希望这些代码可以帮助您或者让您深入了解该主题。如果您有任何补充或建议，请告诉我。感谢您抽出宝贵时间查看此内容！
答案 7 :(得分：0)
我想我遇到了问题：
一旦你使div淡出你没有退出该功能：即使在不透明度变为0之后，fadeout再次调用自身
if(element.style.opacity < 0.0) {
return;
}
也为fadein做同样的事情
答案 8 :(得分：0)
这是我的代码，用于淡入/淡出切换功能。
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;
},
这是来自我所做的jQuery样式的lib。希望它有所帮助。链接到cloud9上的lib： https://c9.io/christopherdumas/magik_wb
答案 9 :(得分：0)
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>
答案 10 :(得分：0)
以下javascript会将元素从不透明度0淡入到调用淡入时的不透明度值。您还可以设置动画的持续时间，这很不错：
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);
}
*基于IBUs answer，但经过修改以考虑以前的不透明度值和设置持续时间的能力，还删除了它所做的无关的CSS更改