一、最简单或者明显的方式是使用定时器
1、在网页中加入布局覆盖真实网页内容
2、使用定时器确定加载所用时间的长短，其实并不是真正的加载进度实现
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>定时器的进度条</title>
<script src="../js/jquery-3.2.1.js"></script>
<script type="text/javascript">
$(function () {
setInterval(function () {
$(".loading").fadeOut();
},3000)
})
</script>
<style type="text/css">
.loading{
width: 100%;
height: 100%;
position: fixed;
top:0;
left:0;
z-index: 100;
background-color: white;
}
.loading .pic{
width: 64px;
height: 64px;
border: 1px solid red;
background: url("./image/35.gif");
position: absolute;
top:0;
bottom: 0;
left: 0;
right:0;
margin: auto;
}
</style>
</head>
<body>
<div class="loading">
<div class="pic"></div>
</div>
<img src="https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=2374531200,2817019640&fm=11&gp=0.jpg" alt=""/>
<img src="https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=1019761374,1197310851&fm=26&gp=0.jpg"/>
<img src="https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=1091681404,1813447708&fm=26&gp=0.jpg">
<img src="https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=4039520080,1420114353&fm=26&gp=0.jpg"/>
</body>
</html>
二、在第一版中做改良
1、理论上还是使用定时器
2、覆盖的内容不在布局中定义而是动态加载
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>定时器的进度条</title>
<script src="../js/jquery-3.2.1.js"></script>
<script type="text/javascript">
$(function () {
var loading = '<div class="loading"><div class="pic"></div></div>';
$("body").append(loading);
setInterval(function () {
$(".loading").fadeOut();
},3000)
})
</script>
<style type="text/css">
.loading{
width: 100%;
height: 100%;
position: fixed;
top:0;
left:0;
z-index: 100;
background-color: white;
}
.loading .pic{
width: 64px;
height: 64px;
border: 1px solid red;
background: url("./image/35.gif");
position: absolute;
top:0;
bottom: 0;
left: 0;
right:0;
margin: auto;
}
</style>
</head>
<body>
<div class="loading">
<div class="pic"></div>
</div>
<img src="https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=2374531200,2817019640&fm=11&gp=0.jpg" alt=""/>
<img src="https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=1019761374,1197310851&fm=26&gp=0.jpg"/>
<img src="https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=1091681404,1813447708&fm=26&gp=0.jpg">
<img src="https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=4039520080,1420114353&fm=26&gp=0.jpg"/>
</body>
</html>
三、通过加载状态实现进度条
document.onreadystatechange 页面加载状态改变时的事件
document.readyState 返回当前文档的状态
uninitialized:还未开始载入
loading:载入中
interactive已加载。文档与用户可以开始交互
complete:载入完成
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>进度条</title>
<style type="text/css">
.loading{
width: 100%;
height: 100%;
position: fixed;
top:0;
left:0;
z-index: 100;
background-color: white;
}
.loading .pic{
width: 64px;
height: 64px;
border: 1px solid red;
background: url("./image/35.gif");
position: absolute;
top:0;
bottom: 0;
left: 0;
right:0;
margin: auto;
}
</style>
<script src="../js/jquery-3.2.1.js"></script>
<script type="text/javascript">
document.onreadystatechange = function () {
console.log(document.readyState);
if(document.readyState=='complete'){
$(".loading").fadeOut();
}
}
</script>
</head>
<body>
<div class="loading">
<div class="pic"></div>
</div>
<img src="https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=2374531200,2817019640&fm=11&gp=0.jpg" alt=""/>
<img src="https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=1019761374,1197310851&fm=26&gp=0.jpg"/>
<img src="https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=1091681404,1813447708&fm=26&gp=0.jpg">
<img src="https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=4039520080,1420114353&fm=26&gp=0.jpg"/>
</body>
</html>
四、使用css创建进度条动画
1、我们可以在https://loading.io/网站上生成css动画图或者获得动画的css样式自己使用
2、我们可以在https://autoprefixer.github.io/?中自动做css的兼容
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>css3创建动画</title>
<style type="text/css">
.loading{
width: 100%;
height: 100%;
position: fixed;
top:0;
left:0;
z-index: 100;
background-color: white;
}
.loading .pic{
width: 50px;
height: 50px;
position: absolute;
top:0;
bottom: 0;
left: 0;
right:0;
margin: auto;
}
.loading .pic i{
display: block;
float: left;
width: 6px;
height: 50px;
background: #399;
margin: 0 2px;
-webkit-transform: scaleY(0.4);
-ms-transform: scaleY(0.4);
transform: scaleY(0.4);
-webkit-animation: load 1.2s infinite;
animation: load 1.2s infinite;
}
.loading .pic i:nth-child(1){
}
.loading .pic i:nth-child(2){
-webkit-animation-delay: 0.1s;
animation-delay: 0.1s;
}
.loading .pic i:nth-child(3){
-webkit-animation-delay: 0.2s;
animation-delay: 0.2s;
}
.loading .pic i:nth-child(4){
-webkit-animation-delay: 0.3s;
animation-delay: 0.3s;
}
.loading .pic i:nth-child(5){
-webkit-animation-delay: 0.4s;
animation-delay: 0.4s;
}
@-webkit-keyframes load {
0%,40%,100%{-webkit-transform: scaleY(0.4);transform: scaleY(0.4)}
20%{-webkit-transform: scaleY(1);transform: scaleY(1)}
}
@keyframes load {
0%,40%,100%{-webkit-transform: scaleY(0.4);transform: scaleY(0.4)}
20%{-webkit-transform: scaleY(1);transform: scaleY(1)}
}
</style>
<script src="../js/jquery-3.2.1.js"></script>
<script type="text/javascript">
document.onreadystatechange = function () {
if(document.readyState == "complete"){
$(".loading").fadeOut();
}
}
</script>
</head>
<body>
<div class="loading">
<div class="pic">
<i></i>
<i></i>
<i></i>
<i></i>
<i></i>
</div>
</div>
<img src="https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=2374531200,2817019640&fm=11&gp=0.jpg" alt=""/>
<img src="https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=1019761374,1197310851&fm=26&gp=0.jpg"/>
<img src="https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=1091681404,1813447708&fm=26&gp=0.jpg">
<img src="https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=4039520080,1420114353&fm=26&gp=0.jpg"/>
</body>
</html>
