以下代码创建一个图像变为白色然后使用另一个图像（demo）更改白色时的效果：
HTML：
<body>
<div class="page-bg" id="page-background1"></div>
<!-- <div class="page-bg" id="page-background2"></div> -->
</body>
JavaScript的：
url = "http://example.com/picture.png";
$("#page-background1")
.animate({
opacity: 0
}, 'slow', function () {
$("#page-background1")
.css({
'background-image': 'url(' + url + ')'
})
.animate({
opacity: 1
});
});
但是我想直接用另一个图像更改一个图像（中间没有白色），但是使用fadeOut / fadeIn效果。我该怎么办？看起来第二个div的使用应该有所帮助，但我找不到有效的解决方案。
答案 0 :(得分：1)
更新后，我尝试应用Stacking elements with Z-index来获得所需的效果。我还创造了一种＆＃34;堆栈＆＃34;对于隐藏的图像更改z-index的图像;与＆＃34; stack＆＃34;中的其他图像相比，最近隐藏的元素被更改为较小的z-index值。该代码支持photos数组中的多个图像，因为它为每个图像创建了一个单独的div。
var photos = [{
url: 'https://drscdn.500px.org/photo/97037403/m=900/d924fc03d69a82a604129011300916be'
}, {
url: 'https://drscdn.500px.org/photo/97037259/m=900/030e1598b7822cd6c41beb4c7a4e466d'
}, {
url: 'https://drscdn.500px.org/photo/97158643/m=900/4ae40d67ef546341111a32f5176694c8'
}];
//z-index, start value -1
//z-index can be either positive or negative value
//based on this answer http://stackoverflow.com/a/491105/2048391
var zIndex = -1;
//first foto in the array shown/hidden first
var visibleIndex = 0;
//initialize
//by creating div for each image/url
for (i = 0; i < photos.length; i++) {
var div = document.createElement("div");
div.id = "page-background" + (i + 1);
div.setAttribute("class", "page-bg");
div.style.zIndex = zIndex;
var url = "url('" + photos[i].url + "')";
div.style.background = "#505D6E " + url + " no-repeat center center fixed";
document.body.appendChild(div);
zIndex = zIndex - 1;
//and add div id to the photos array
photos[i].id = "page-background" + (i + 1);
}
function changeBackground() {
var hideItemIndex = visibleIndex % photos.length;
var showItemIndex = (visibleIndex + 1) % photos.length;
var hideItemId = "#" + photos[hideItemIndex].id;
var showItemId = "#" + photos[showItemIndex].id;
//hide current image with animation
//after which show the next image with animation
$(hideItemId).animate({
opacity: 0
}, "slow", function() {
$(showItemId)
.animate({
opacity: 1
}, "slow");
//change z-index for the item that was hidden
//by moving it to the bottom of the stack
$(hideItemId).css("z-index", zIndex);
$(hideItemId).css("opacity", 1);
});
zIndex = zIndex - 1;
visibleIndex = visibleIndex + 1;
}
//make sure that there's at least 2 images in the array
if (photos.length > 1) {
setInterval(function() {
changeBackground();
}, 2000);
}.page-bg {
border: 1px solid black;
height: 100%;
width: 100%;
position: absolute;
top: 0;
left: 0;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
做同样事情的替代方式。下面只有可见和下一个div元素存在，并且出于性能原因删除隐藏的div，如LA _
所示
var photos = [{
url: 'https://drscdn.500px.org/photo/97037403/m=900/d924fc03d69a82a604129011300916be'
}, {
url: 'https://drscdn.500px.org/photo/97037259/m=900/030e1598b7822cd6c41beb4c7a4e466d'
}, {
url: 'https://drscdn.500px.org/photo/97158643/m=900/4ae40d67ef546341111a32f5176694c8'
}];
//z-index, start value 100000
//z-index could be a larger number
//based on this answer http://stackoverflow.com/a/491105/2048391
var zIndex = -1;
//first foto in the array shown/hidden first
var visibleIndex = 0;
//initialize
//by creating div for each image/url
for (i = 0; i < photos.length; i++) {
//only two images are created
if (i < 2)
createDiv(i, (i + 1) );
//and add div id to the photos array
photos[i].id = "page-background" + (i + 1);
}
function changeBackground() {
var hideItemIndex = visibleIndex % photos.length;
var showItemIndex = (visibleIndex + 1) % photos.length;
var hideItemId = "#" + photos[hideItemIndex].id;
var showItemId = "#" + photos[showItemIndex].id;
//hide current image with animation
//after which show the next image with animation
$(hideItemId).animate({
opacity: 0
}, "slow", function () {
$(showItemId)
.animate({
opacity: 1
}, "slow");
//remove the item that was hidden
$(hideItemId).remove();
});
var nextItemIndex = (visibleIndex + 2) % photos.length;
//create the next div with picture
createDiv(nextItemIndex, (nextItemIndex + 1) );
visibleIndex = visibleIndex + 1;
}
//make sure that there is at least 2 photos
if (photos.length > 1) {
setInterval(function () {
changeBackground();
}, 2000);
}
function createDiv(index, divIdNro) {
var div = document.createElement("div");
div.id = "page-background" + divIdNro;
div.setAttribute("class", "page-bg");
div.style.zIndex = zIndex;
var url = "url('" + photos[index].url + "')";
//div.style.backgroundImage = url;
div.style.background = "#505D6E " + url + " no-repeat center center fixed";
document.body.appendChild(div);
zIndex = zIndex - 1;
}.page-bg {
border:1px solid black;
height:100%;
width: 100%;
position: absolute;
top: 0;
left: 0;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
答案 1 :(得分：0)
这里有一个fiddle作为片段不能正常工作，你可以将淡入淡出的速度设置为毫秒或关键字，它的速度很慢。我点击了按钮并且没有在网址中传递但是取出我的按钮点击功能并将代码放入你的setinterval函数中，同时将jquery中的url设置回url变量
$('button').on('click',function(){
$("#page-background1").fadeOut( "slow", function() {
$("#page-background1")
.css({
'background-image': 'url(http://lorempixel.com/400/400/sports/2)'
});});
$("#page-background1").fadeIn('slow');
});.page-bg{
min-width:500px;
min-height:500px;
}
#page-background1{
background-image: url(http://lorempixel.com/400/400/sports/1);
background-size:400px 400px;
background-repeat: no-repeat;
}<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button>Click me to change the background</button>
<div class="page-bg" id="page-background1">;</div>
答案 2 :(得分：0)
将javascript更改为：
url = "http://example.com/picture.png";
.animate({
opacity: 0.5
}, 'fast', function () {
$("#page-background1")
.css({
'background-image': 'url(' + url + ')'
})
.animate({
opacity: 1
});
});