版权声明： https://blog.csdn.net/qq_41115965/article/details/83713343
网页进度条制作
一、为什么需要网页进度条
随着HTML的普及，各种CSS3动画及特效在网页中层出不穷，PC端载入数据的速度还算可以，移动端相对要慢很多，如果图片或脚本没有完全载入，用户在操作中可能发生各种问题，因此我们需要对载入数据进行检测，以更加人性化的方式给用户展现。
二、常见进度条的样式
- 百分比形式
- 旋转动画
- 固定在顶部的线条
三、进度条制作
加载进度条的制作，需要通过加载状态事件，才是正确的结合实际情况的做法。
需要使用的方法：
- document.onreadystatechange 页面加载状态改变时的事件
- document.readystate 返回文档当前的状态
状态值：
- uninitialized 还未开始载入
- loading 载入中
- interactive 已加载，文档与用户开始交互
- complete 载入完成
四、具体代码
CSS样式文件
/* 加载动画样式start */
.loading {
width: 100%;
height: 100%;
position: fixed;
top: 0;
left: 0;
z-index: 100;
background: #ffffff;
}
.loading .picture {
position: absolute;
top: 0;
left: 0;
bottom: 0;
right: 0;
margin: auto;
background: url(img/loading.gif);
width: 150px;
height: 150px;
}
/* 加载动画样式end */
js文件（重要）
<script src="https://code.jquery.com/jquery-3.1.1.min.js" type="text/javascript" charset="utf-8"></script>
<script type="text/javascript">
document.onreadystatechange = function() {
console.log(document.readyState)
if (document.readyState == 'complete') {
console.log(document.readyState, '11111111111')
$('.loading').fadeOut();
}
}
</script>
五、步骤总结
- 首先，我们在 htm l文件中定义 loading 的结构；
- 而后，在 css 文件中书写对应的样式文件；
- 最后，在 js 文件中，我们使用 onreadystatechange 在时机中，我们通过判断 readyState 的值，决定隐藏 loading 结构的隐藏即可。
六、完整代码分享
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>进度条动画制作</title>
<style type="text/css">
* {
margin: 0;
padding: 0;
}
/* 加载动画样式start */
.loading {
width: 100%;
height: 100%;
position: fixed;
top: 0;
left: 0;
z-index: 100;
background: #ffffff;
}
.loading .picture {
position: absolute;
top: 0;
left: 0;
bottom: 0;
right: 0;
margin: auto;
background: url(img/loading.gif);
width: 150px;
height: 150px;
}
/* 加载动画样式end */
/* 页面样式start */
.container {
width: 1200px;
margin: 100px auto;
border: 1px solid red;
padding: 20px;
overflow: hidden;
border-radius: 10px;
}
.container .item {
float: left;
margin-bottom: 10px;
}
.container img {
font-size: 0;
vertical-align: middle;
width: 300px;
height: 200px;
}
/* 页面样式end */
</style>
</head>
<body>
<div class="loading">
<div class="picture"></div>
</div>
<!-- 注意：以下结构仅仅是为了演示页面而已 -->
<div class="container">
<div class="item">
<img src="http://pic1.win4000.com/wallpaper/2018-01-06/5a50674a7b626.jpg">
</div>
<div class="item">
<img src="http://img2.imgtn.bdimg.com/it/u=2398464402,4254570216&fm=11&gp=0.jpg">
</div>
<div class="item">
<img src="http://i0.hdslb.com/bfs/article/669b74844e47c4ca9774aad43dc62b0d879fbcd6.jpg">
</div>
<div class="item">
<img src="http://pic1.win4000.com/wallpaper/2018-06-08/5b1a448a79175.jpg">
</div>
<div class="item">
<img src="http://img0.imgtn.bdimg.com/it/u=228361023,682353921&fm=26&gp=0.jpg">
</div>
<div class="item">
<img src="http://img5.imgtn.bdimg.com/it/u=550633143,1906543664&fm=11&gp=0.jpg">
</div>
<div class="item">
<img src="http://www.wallcoo.com/flower/digital_flower_jp_03/wallpapers/1680x1050/wallcoo.com_Digital_Flower_Photo_321.jpg">
</div>
<div class="item">
<img src="http://www.wallcoo.com/nature/2009_Landscape_1680_Desktop_04/wallpapers/1680x1050/Rising%20Mist%20at%20Dawn.jpg">
</div>
<div class="item">
<img src="http://www.wallcoo.com/photograph/Fresh%20Vegetables%20by%20Isabelle%20Rozenbaum/wallpapers/1440x900/Bunch%20of%20radishes%2C%20close-up.jpg">
</div>
<div class="item">
<img src="http://img2.niutuku.com/desk/1208/2044/ntk-2044-14905.jpg">
</div>
<div class="item">
<img src="http://www.wallcoo.com/cartoon/Semafore_Calendar_Project_1920/wallpapers/1280x800/Calendar_Design_2003.04.jpg">
</div>
<div class="item">
<img src="http://www.wallcoo.com/cartoon/future_tech_background/wallpapers/1680x1050/%5Bwallcoo_com%5D_3516_future_TECH_Image.jpg">
</div>
<div class="item">
<img src="http://i1.3conline.com/images/piclib/201305/20/batch/1/176010/13690210721960gaa56pug9.jpg">
</div>
<div class="item">
<img src="http://img2.niutuku.com/desk/1207/1030/ntk119230.jpg">
</div>
<div class="item">
<img src="http://img2.niutuku.com/desk/1207/1041/ntk120340.jpg">
</div>
<div class="item">
<img src="http://g.hiphotos.baidu.com/zhidao/pic/item/6a600c338744ebf814066acedbf9d72a6159a7cf.jpg">
</div>
<div class="item">
<img src="http://pic1.win4000.com/wallpaper/3/510b709821ec1.jpg">
</div>
<div class="item">
<img src="http://download.firefox.com.cn/gfox/wallpaper/2013/06/1920x1200.jpg">
</div>
<div class="item">
<img src="http://pic9.nipic.com/20100825/668573_135507057246_2.jpg">
</div>
<div class="item">
<img src="http://pic1.win4000.com/wallpaper/a/51f1e196b5576.jpg">
</div>
<div class="item">
<img src="http://img2.imgtn.bdimg.com/it/u=3757609547,3947405383&fm=214&gp=0.jpg">
</div>
<div class="item">
<img src="http://img4.imgtn.bdimg.com/it/u=2295877184,3273384647&fm=214&gp=0.jpg">
</div>
<div class="item">
<img src="http://i0.hdslb.com/bfs/article/9a3129c90c5da974176a74b4bbe782f1253fb8d2.jpg">
</div>
<div class="item">
<img src="http://i0.hdslb.com/bfs/article/d6d373a850c45beb250a7cbdcab1176551206740.jpg@1320w_934h.jpg">
</div>
<div class="item">
<img src="http://i0.hdslb.com/bfs/article/5350896be8e02fa2e673591380956fbf884a9e76.jpg">
</div>
<div class="item">
<img src="http://i0.hdslb.com/bfs/article/5278e12727d1ccd794a1c990905675e9b9992cce.jpg">
</div>
<div class="item">
<img src="http://img.club.pchome.net/upload/club/other/2006/6/4/nrq_1149351040.jpg">
</div>
<div class="item">
<img src="http://pic1.win4000.com/wallpaper/1/5791e7b252e81.jpg">
</div>
</div>
</body>
</html>
<script src="https://code.jquery.com/jquery-3.1.1.min.js" type="text/javascript" charset="utf-8"></script>
<script type="text/javascript">
document.onreadystatechange = function() {
console.log(document.readyState)
if (document.readyState == 'complete') {
console.log(document.readyState, '11111111111')
$('.loading').fadeOut();
}
}
</script>