我们经常在浏览网页的时候会看到数据在加载时，出现的LOADING提示。其实这个功能原理是很简单的，就是一个DIV遮盖当前页面，然后Loading就在遮盖DIV层上展示出来，现在我们来动手实现一下。
1.当前页面：
<div class="current"><a href="#" onclick="showLoading()">Loading</a></div>
2.遮罩层：
<div id="over" class="over"></div>
3.Loading展示层：
<div id="layout" class="layout"><img src="http://images.cnblogs.com/cnblogs_com/qiuyan/477435/o_31.gif" /></div>
整体代码:
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<style type="text/css">
.current a {
font-size: 20px;
}
.over {
display: none;
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
background-color: #f5f5f5;
opacity:0.5;
z-index: 1000;
}
.layout {
display: none;
position: absolute;
top: 40%;
left: 40%;
width: 20%;
height: 20%;
z-index: 1001;
text-align:center;
}
</style>
<script type="text/javascript">
function showLoading()
{
document.getElementById("over").style.display = "block";
document.getElementById("layout").style.display = "block";
}
</script>
</head>
<body>
<div class="current"><a href="#" onclick="showLoading()">Loading</a></div>
<div id="over" class="over"></div>
<div id="layout" class="layout"><img src="http://images.cnblogs.com/cnblogs_com/qiuyan/477435/o_31.gif" /></div>
</body>
</html>
1 <!DOCTYPE html>
2 <html xmlns="http://www.w3.org/1999/xhtml">
3 <head>
4 <title></title>
5 <style type="text/css">
6 .current a {
7 font-size: 20px;
8 }
9
10 .over {
11 display: none;
12 position: absolute;
13 top: 0;
14 left: 0;
15 width: 100%;
16 height: 100%;
17 background-color: #f5f5f5;
18 opacity:0.5;
19 z-index: 1000;
20 }
21
22 .layout {
23 display: none;
24 position: absolute;
25 top: 40%;
26 left: 40%;
27 width: 20%;
28 height: 20%;
29 z-index: 1001;
30 text-align:center;
31 }
32 </style>
33 <script type="text/javascript">
34 function showLoading()
35 {
36 document.getElementById("over").style.display = "block";
37 document.getElementById("layout").style.display = "block";
38 }
39 </script>
40 </head>
41 <body>
42 <div class="current"><a href="#" onclick="showLoading()">Loading</a></div>
43 <div id="over" class="over"></div>
44 <div id="layout" class="layout"><img src="http://images.cnblogs.com/cnblogs_com/qiuyan/477435/o_31.gif" /></div>
45 </body>
46 </html>
最终效果：
在网上还看到另外一种实现方式，感觉思路不错，就是利用JS不断的改变html标签的value值，达到加载提示的效果，根据他的思路我自己实现了下，代码如下：
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<!-- <script src="Scripts/jquery-1.8.2.js"></script>-->
<style type="text/css">
#tb {
width: 100%;
height: 100%;
line-height: 10px;
}
#tb tr td {
text-align: center;
}
.progressbar {
font-family: Arial;
font-weight: bolder;
color: gray;
background-color: white;
padding: 0px;
border-style: none;
}
.percent {
font-family: Arial;
color: gray;
text-align: center;
border-width: medium;
border-style: none;
}
</style>
<script type="text/javascript">
var bar = 0;
var step = "||";
/*
*第一种方式即 ：$(document).ready(function(){.....});
*/
//$(function () {
// progress();
//});
/*
*第二种方式
*/
//window.onload = function () {
// progress();
//}
/*
*第三种方式模拟 $(document).ready(function(){.....});
*/
(function () {
var ie = !!(window.attachEvent && !window.opera);
var wk = /webkit\/(\d+)/i.test(navigator.userAgent) && (RegExp.$1 < 525);
var fn = [];
var run = function () { for (var i = 0; i < fn.length; i++) fn[i](); };
var d = document;
d.ready = function (f) {
if (!ie && !wk && d.addEventListener)
return d.addEventListener('DOMContentLoaded', f, false);
if (fn.push(f) > 1) return;
if (ie)
(function () {
try { d.documentElement.doScroll('left'); run(); }
catch (err) { setTimeout(arguments.callee, 0); }
})();
else if (wk)
var t = setInterval(function () {
if (/^(loaded|complete)$/.test(d.readyState))
clearInterval(t), run();
}, 0);
};
})();
document.ready(function () {
progress();
});
function progress() {
bar = bar + 2;
step = step + "||";
document.getElementById("percent").value = bar + "%";
document.getElementById("progressbar").value = step;
if (bar <= 98) {
setTimeout("progress()", 100);
}
}
</script>
</head>
<body>
<table id="tb">
<tr>
<td>
<input type="text" size="50" class="percent" id="percent" /></td>
</tr>
<tr>
<td>
<input type="text" size="50" class="progressbar" id="progressbar" /></td>
</tr>
</table>
</body>
</html>
1 <!DOCTYPE html>
2 <html xmlns="http://www.w3.org/1999/xhtml">
3 <head>
4 <title></title>
5 <!-- <script src="Scripts/jquery-1.8.2.js"></script>-->
6 <style type="text/css">
7 #tb {
8 width: 100%;
9 height: 100%;
10 line-height: 10px;
11 }
12
13 #tb tr td {
14 text-align: center;
15 }
16
17 .progressbar {
18 font-family: Arial;
19 font-weight: bolder;
20 color: gray;
21 background-color: white;
22 padding: 0px;
23 border-style: none;
24 }
25
26 .percent {
27 font-family: Arial;
28 color: gray;
29 text-align: center;
30 border-width: medium;
31 border-style: none;
32 }
33 </style>
34 <script type="text/javascript">
35 var bar = 0;
36 var step = "||";
37 /*
38 *第一种方式即 ：$(document).ready(function(){.....});
39 */
40 //$(function () {
41 // progress();
42 //});
43
44 /*
45 *第二种方式
46 */
47 //window.onload = function () {
48 // progress();
49 //}
50
51 /*
52 *第三种方式模拟 $(document).ready(function(){.....});
53 */
54 (function () {
55 var ie = !!(window.attachEvent && !window.opera);
56 var wk = /webkit\/(\d+)/i.test(navigator.userAgent) && (RegExp.$1 < 525);
57 var fn = [];
58 var run = function () { for (var i = 0; i < fn.length; i++) fn[i](); };
59 var d = document;
60 d.ready = function (f) {
61 if (!ie && !wk && d.addEventListener)
62 return d.addEventListener('DOMContentLoaded', f, false);
63 if (fn.push(f) > 1) return;
64 if (ie)
65 (function () {
66 try { d.documentElement.doScroll('left'); run(); }
67 catch (err) { setTimeout(arguments.callee, 0); }
68 })();
69 else if (wk)
70 var t = setInterval(function () {
71 if (/^(loaded|complete)$/.test(d.readyState))
72 clearInterval(t), run();
73 }, 0);
74 };
75 })();
76
77 document.ready(function () {
78
79 progress();
80
81 });
82
83
84 function progress() {
85 bar = bar + 2;
86 step = step + "||";
87 document.getElementById("percent").value = bar + "%";
88 document.getElementById("progressbar").value = step;
89 if (bar <= 98) {
90 setTimeout("progress()", 100);
91 }
92 }
93 </script>
94 </head>
95 <body>
96 <table id="tb">
97 <tr>
98 <td>
99 <input type="text" size="50" class="percent" id="percent" /></td>
100 </tr>
101 <tr>
102 <td>
103 <input type="text" size="50" class="progressbar" id="progressbar" /></td>
104 </tr>
105 </table>
106 </body>
107 </html>
最终效果：