默認情況下如果網站請求速度慢，所以會有一段時間的空白頁面等等，用戶體驗效果不好，見到很多的頁面都有預加載的效果，加載之前先加載一個動畫，後臺進程繼續加載頁面內容，當頁面內容加載完之後再退出動畫顯示內容，這樣的用戶體驗更好。
例如此鏈接：http://crusader12.com/C12HoverAlls/
這篇文章是從上面鏈接的內容上拔下來的，操作流程很簡單，只有兩部如下
首先定義一個loader.css文件，如下內容
.chromeframe {
margin: 0.2em 0;
background: #ccc;
color: #000;
padding: 0.2em 0;}
#loader-wrapper {
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 100%;
z-index:999999;}
#loader {
display: block;
position: relative;
left: 50%;
top: 50%;
width: 150px;
height: 150px;
margin: -75px 0 0 -75px;
border-radius: 50%;
border: 3px solid transparent;
/* COLOR 1 */
border-top-color: #FFF;
-webkit-animation: spin 2s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
-ms-animation: spin 2s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
-moz-animation: spin 2s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
-o-animation: spin 2s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
animation: spin 2s linear infinite; /* Chrome, Firefox 16+, IE 10+, Opera */
z-index:1001;}
#loader:before {
content: "";
position: absolute;
top: 5px;
left: 5px;
right: 5px;
bottom: 5px;
border-radius: 50%;
border: 3px solid transparent;
/* COLOR 2 */
border-top-color: #FFF;
-webkit-animation: spin 3s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
-moz-animation: spin 3s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
-o-animation: spin 3s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
-ms-animation: spin 3s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
animation: spin 3s linear infinite; /* Chrome, Firefox 16+, IE 10+, Opera */}
#loader:after {
content: "";
position: absolute;
top: 15px;
left: 15px;
right: 15px;
bottom: 15px;
border-radius: 50%;
border: 3px solid transparent;
border-top-color: #FFF;
/* COLOR 3 */
-moz-animation: spin 1.5s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
-o-animation: spin 1.5s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
-ms-animation: spin 1.5s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
-webkit-animation: spin 1.5s linear infinite; /* Chrome, Opera 15+, Safari 5+ */
animation: spin 1.5s linear infinite; /* Chrome, Firefox 16+, IE 10+, Opera */}
@-webkit-keyframes spin {
0%{
-webkit-transform: rotate(0deg); /* Chrome, Opera 15+, Safari 3.1+ */
-ms-transform: rotate(0deg); /* IE 9 */
transform: rotate(0deg); /* Firefox 16+, IE 10+, Opera */
}100%{
-webkit-transform: rotate(360deg); /* Chrome, Opera 15+, Safari 3.1+ */
-ms-transform: rotate(360deg); /* IE 9 */
transform: rotate(360deg); /* Firefox 16+, IE 10+, Opera */}
}
@keyframes spin {
0%{
-webkit-transform: rotate(0deg); /* Chrome, Opera 15+, Safari 3.1+ */
-ms-transform: rotate(0deg); /* IE 9 */
transform: rotate(0deg); /* Firefox 16+, IE 10+, Opera */
}100%{
-webkit-transform: rotate(360deg); /* Chrome, Opera 15+, Safari 3.1+ */
-ms-transform: rotate(360deg); /* IE 9 */
transform: rotate(360deg); /* Firefox 16+, IE 10+, Opera */}
}
#loader-wrapper .loader-section {
position: fixed;
top: 0;
width: 51%;
height: 100%;
background: #1abc9c; /* Old browsers */
z-index: 1000;
-webkit-transform: translateX(0); /* Chrome, Opera 15+, Safari 3.1+ */
-ms-transform: translateX(0); /* IE 9 */
transform: translateX(0); /* Firefox 16+, IE 10+, Opera */}
#loader-wrapper .loader-section.section-left {left: 0;}
#loader-wrapper .loader-section.section-right {right: 0;}
/* Loaded */
.loaded #loader-wrapper .loader-section.section-left {
-webkit-transform: translateX(-100%); /* Chrome, Opera 15+, Safari 3.1+ */
-ms-transform: translateX(-100%); /* IE 9 */
transform: translateX(-100%); /* Firefox 16+, IE 10+, Opera */
-webkit-transition: all 0.7s 0.3s cubic-bezier(0.645, 0.045, 0.355, 1.000);
transition: all 0.7s 0.3s cubic-bezier(0.645, 0.045, 0.355, 1.000);}
.loaded #loader-wrapper .loader-section.section-right {
-webkit-transform: translateX(100%); /* Chrome, Opera 15+, Safari 3.1+ */
-ms-transform: translateX(100%); /* IE 9 */
transform: translateX(100%); /* Firefox 16+, IE 10+, Opera */
-webkit-transition: all 0.7s 0.3s cubic-bezier(0.645, 0.045, 0.355, 1.000);
transition: all 0.7s 0.3s cubic-bezier(0.645, 0.045, 0.355, 1.000);}
.loaded #loader {
opacity: 0;
-webkit-transition: all 0.3s ease-out;
transition: all 0.3s ease-out;}
.loaded #loader-wrapper {
visibility: hidden;
-webkit-transform: translateY(-100%); /* Chrome, Opera 15+, Safari 3.1+ */
-ms-transform: translateY(-100%); /* IE 9 */
transform: translateY(-100%); /* Firefox 16+, IE 10+, Opera */
-webkit-transition: all 0.3s 1s ease-out;
transition: all 0.3s 1s ease-out;}
/* JavaScript Turned Off */
.no-js #loader-wrapper {display: none;}
.no-js h1 {color: #222222;}
#loader-wrapper .load_title {
font-family:'Open Sans';
color:#FFF; font-size:19px; width:100%; text-align:center; z-index:9999999999999; position:absolute; top:60%; opacity:1; line-height:30px; }
#loader-wrapper .load_title span { font-weight:normal; font-style:italic; font-size:13px; color:#FFF; opacity:0.5;}
第二步：在網站頁面header標籤和body標籤加入以下代碼
// 引入jquery
<!--頁面加載start-->
<link rel="stylesheet" type="text/css" href="css/loader.min.css">
<script type="text/javascript">
// 等待所有加載
$(window).load(function(){
$('body').addClass('loaded');
$('#loader-wrapper .load_title').remove();
});
</script>
<div id="loader-wrapper">
<div id="loader"></div>
<div class="loader-section section-left"></div>
<div class="loader-section section-right"></div>
<div class="load_title">正在加載LoveFeel站點<br><span>V1.0</span></div>
</div>
<!--頁面加載end-->
HoverAlls頁面源碼如下操作，他先是加載一段json封裝之後再顯示內容的，我上面的代碼省去了json的操作。
$(window).load(function(){
$('body').addClass('loaded').Chameleon({
'current_item':'hoveralls',
'json_url':'../Envato/items.json'
});
$('#loader-wrapper .load_title').remove();
});
查看原文：http://www.ibloger.net/article/401.html