CSS3 隨機背景圖片切換特效

CSS3 隨機背景圖片淡入淡出切換特效演示效果如本篇文章背景所示看大家扒我的幻想領域二次元限定版扒得比較累，扒了大半個小時的，抽空整理一下發出來設計之初本來是打算使用 jQuery 進行實現的，但是注意到了 CSS3 的 @keyframes 規則，CSS3 已經強大到曾經只有 JS 才能實現的效果

定義和用法

透過 @keyframes 規則，您能夠建立動畫。

建立動畫的原理是，將一套 CSS 樣式逐漸變化為另一套樣式。

在動畫過程中，您能夠多次改變這套 CSS 樣式。

以百分比來規定改變發生的時間，或者透過關鍵詞 “from” 和 “to”，等價於 0% 和 100%。

0% 是動畫的開始時間，100% 是動畫的結束時間。

為了獲得最佳的瀏覽器支援，您應該始終定義 0% 和 100% 選擇器。

註釋：請使用動畫屬性來控制動畫的外觀，同時將動畫與選擇器綁定。

核心 CSS 部分 (記得切換圖片地址)

body {
	background: #000;
	background-attachment: fixed;
	word-wrap: break-word;
	-webkit-background-size: cover;
	-moz-background-size: cover;
	background-size: cover;
	background-repeat: no-repeat
}

ul {
	list-style: none
}

.cb-slideshow li:nth-child(1) span {
	background-image: url(https://random.52ecy.cn/randbg.php?v=1520341099)
}

.cb-slideshow li:nth-child(2) span {
	background-image: url(https://random.52ecy.cn/randbg.php?v=1520341159)
}

.cb-slideshow li:nth-child(3) span {
	background-image: url(https://random.52ecy.cn/randbg.php?v=1520341149)
}

.cb-slideshow li:nth-child(4) span {
	background-image: url(https://random.52ecy.cn/randbg.php?v=1520341139)
}

.cb-slideshow li:nth-child(5) span {
	background-image: url(https://random.52ecy.cn/randbg.php?v=1520341129)
}

.cb-slideshow li:nth-child(6) span {
	background-image: url(https://random.52ecy.cn/randbg.php?v=1520341119)
}

.cb-slideshow,.cb-slideshow:after {
	position: fixed;
	width: 100%;
	height: 100%;
	top: 0;
	left: 0;
	z-index: -2
}

.cb-slideshow:after {
	content: ''
}

.cb-slideshow li span {
	width: 100%;
	height: 100%;
	position: absolute;
	top: 0;
	left: 0;
	color: transparent;
	background-size: cover;
	background-position: 50% 50%;
	background-repeat: none;
	opacity: 0;
	z-index: -2;
	-webkit-backface-visibility: hidden;
	-webkit-animation: imageAnimation 36s linear infinite 0s;
	-moz-animation: imageAnimation 36s linear infinite 0s;
	-o-animation: imageAnimation 36s linear infinite 0s;
	-ms-animation: imageAnimation 36s linear infinite 0s;
	animation: imageAnimation 36s linear infinite 0s
}

.cb-slideshow li:nth-child(2) span {
	-webkit-animation-delay: 6s;
	-moz-animation-delay: 6s;
	-o-animation-delay: 6s;
	-ms-animation-delay: 6s;
	animation-delay: 6s
}

.cb-slideshow li:nth-child(3) span {
	-webkit-animation-delay: 12s;
	-moz-animation-delay: 12s;
	-o-animation-delay: 12s;
	-ms-animation-delay: 12s;
	animation-delay: 12s
}

.cb-slideshow li:nth-child(4) span {
	-webkit-animation-delay: 18s;
	-moz-animation-delay: 18s;
	-o-animation-delay: 18s;
	-ms-animation-delay: 18s;
	animation-delay: 18s
}

.cb-slideshow li:nth-child(5) span {
	-webkit-animation-delay: 24s;
	-moz-animation-delay: 24s;
	-o-animation-delay: 24s;
	-ms-animation-delay: 24s;
	animation-delay: 24s
}

.cb-slideshow li:nth-child(6) span {
	-webkit-animation-delay: 30s;
	-moz-animation-delay: 30s;
	-o-animation-delay: 30s;
	-ms-animation-delay: 30s;
	animation-delay: 30s
}

@-webkit-keyframes imageAnimation {
	0% {
		opacity: 0;
		-webkit-animation-timing-function: ease-in
	}

	8% {
		opacity: 1;
		-webkit-transform: scale(1.05);
		-webkit-animation-timing-function: ease-out
	}

	17% {
		opacity: 1;
		-webkit-transform: scale(1.1) rotate(0)
	}

	25% {
		opacity: 0;
		-webkit-transform: scale(1.1) rotate(0)
	}

	100% {
		opacity: 0
	}
}

當然還是需要配合 HTML 程式碼的 HTML 部分 (其中的文字部分和 <li> 的數量是可以隨意更改的)

<ul class="cb-slideshow">
	<li>
		<span>幻想</span></li>
	<li>
		<span>領域</span></li>
	<li>
		<span>一個</span></li>
	<li>
		<span>專業的</span></li>
	<li>
		<span>二次元</span></li>
	<li>
		<span>圖床</span></li>
</ul>

注意：<li> 的數量要和 CSS 對應上，並且至少要兩個以上。另外 IE 瀏覽器是不支援 CSS3 的特效

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body{background:#000;background-attachment:fixed;word-wrap:break-word;-webkit-background-size:cover;-moz-background-size:cover;background-size:cover;background-repeat:no-repeat}ul{z-index:99;list-style:none}li{list-style: none;}.cb-slideshow li:nth-child(1) span{background-image:url(https://random.52ecy.cn/randbg.php?v=1520341099)}.cb-slideshow li:nth-child(2) span{background-image:url(https://random.52ecy.cn/randbg.php?v=1520341159)}.cb-slideshow li:nth-child(3) span{background-image:url(https://random.52ecy.cn/randbg.php?v=1520341149)}.cb-slideshow li:nth-child(4) span{background-image:url(https://random.52ecy.cn/randbg.php?v=1520341139)}.cb-slideshow li:nth-child(5) span{background-image:url(https://random.52ecy.cn/randbg.php?v=1520341129)}.cb-slideshow li:nth-child(6) span{background-image:url(https://random.52ecy.cn/randbg.php?v=1520341119)}.cb-slideshow,.cb-slideshow:after{position:fixed;width:100%;height:100%;top:0;left:0;z-index:-2}.cb-slideshow:after{content:''}.cb-slideshow li span{width:100%;height:100%;position:absolute;top:0;left:0;color:transparent;background-size:cover;background-position:50% 50%;background-repeat:none;opacity:0;z-index:-2;-webkit-backface-visibility:hidden;-webkit-animation:imageAnimation 36s linear infinite 0s;-moz-animation:imageAnimation 36s linear infinite 0s;-o-animation:imageAnimation 36s linear infinite 0s;-ms-animation:imageAnimation 36s linear infinite 0s;animation:imageAnimation 36s linear infinite 0s}.cb-slideshow li:nth-child(2) span{-webkit-animation-delay:6s;-moz-animation-delay:6s;-o-animation-delay:6s;-ms-animation-delay:6s;animation-delay:6s}.cb-slideshow li:nth-child(3) span{-webkit-animation-delay:12s;-moz-animation-delay:12s;-o-animation-delay:12s;-ms-animation-delay:12s;animation-delay:12s}.cb-slideshow li:nth-child(4) span{-webkit-animation-delay:18s;-moz-animation-delay:18s;-o-animation-delay:18s;-ms-animation-delay:18s;animation-delay:18s}.cb-slideshow li:nth-child(5) span{-webkit-animation-delay:24s;-moz-animation-delay:24s;-o-animation-delay:24s;-ms-animation-delay:24s;animation-delay:24s}.cb-slideshow li:nth-child(6) span{-webkit-animation-delay:30s;-moz-animation-delay:30s;-o-animation-delay:30s;-ms-animation-delay:30s;animation-delay:30s}@-webkit-keyframes imageAnimation{0%{opacity:0;-webkit-animation-timing-function:ease-in}8%{opacity:1;-webkit-transform:scale(1.05);-webkit-animation-timing-function:ease-out}17%{opacity:1;-webkit-transform:scale(1.1) rotate(0)}25%{opacity:0;-webkit-transform:scale(1.1) rotate(0)}100%{opacity:0}}