loading.js简单实现

1.用于网页中数据加载时等待。效果简洁明了,显得界面更清爽自然:
2.实现简单,方便使用,只需一张图片loading.gif和一个loading.js,无样式。
源码+Demo下载:https://files.cnblogs.com/zhougaojun/loading.js.zip
3.js代码:
 1 /**
 2  * html Loading...
 3  * @return {}
 4  * @auth  goolser
 5  * @date  2015-1-5 
 6  */
 7     var Loading = {
 8         handler:null, //setInterval执行函数的句柄
 9         text:'Loading...', //Loading默认显示的文字
10         //获取滚动条距离上边顶部的距离
11         getScrollTop:function(){   
12             var scrollTop=0;   
13             if(document.documentElement&&document.documentElement.scrollTop){   
14                 scrollTop=document.documentElement.scrollTop;   
15             }else if(document.body){   
16                 scrollTop=document.body.scrollTop;   
17             }   
18             return scrollTop;   
19         },
20          //获取内部内容的总高度,
21          getScrollHeight:function(){   
22             return Math.max(document.body.scrollHeight,document.documentElement.scrollHeight);   
23         },
24         //是获取可见内容的高度
25         getHeight: function(){
26             if(window.innerHeight!= undefined){
27                 return window.innerHeight;
28             }else{
29                 var B= document.body, D= document.documentElement;
30                 return Math.min(D.clientHeight, B.clientHeight) 
31                 } 
32             },
33         //显示阴影
34         showShadow:function(){
35             var maskHeight = this.getScrollHeight()+"px";
36             var shadowDiv =  document.createElement("div");
37             shadowDiv.innerHTML = "";
38             shadowDiv.setAttribute('id','shadowDiv_MASK');
39             shadowDiv.setAttribute('style','position:fixed; position: absolute; z-index: 999;left:0;top:0;display:block;100%;height:'+maskHeight+'; opacity:0.6;filter: alpha(opacity=60);-moz-opacity: 0.6; background:#000;');
40             var body = document.getElementsByTagName("body")[0];
41             body.appendChild(shadowDiv);
42         },
43         //关闭阴影
44         hideShadow:function(){
45             var body = document.getElementsByTagName("body")[0];
46             var shadowDiv_MASK = document.getElementById('shadowDiv_MASK');
47             if(body && shadowDiv_MASK){
48                 body.removeChild(shadowDiv_MASK);
49             }
50         },
51         //显示Loading
52         show:function(txt){
53             var top = this.getScrollTop()+(this.getHeight()/2)+"px";
54             Loading.showShadow();
55             var me = this;
56             if(txt){
57                 me.text = txt;
58             }
59             var loadingDiv =  document.createElement("div");
60             loadingDiv.innerHTML = me.text;
61             loadingDiv.setAttribute('id','loadingDiv');
62             loadingDiv.setAttribute('style','padding:5px;top:'+top+';left:50%;margin:-9px 0 0 -75px;z-index: 9999;text-indent:20px; background:  url("img/loading.gif")  no-repeat #fff 5px 50%;border:1px solid #0099cc;color:#0099cc;font-size:12px;150px;line-height:17px; height:18px;position:absolute;');
63             var body = document.getElementsByTagName("body")[0];
64             body.appendChild(loadingDiv);
65             var flag = true;
66             handler=setInterval(function(){
67                 if(flag){
68                     loadingDiv.innerHTML = "";
69                     flag = false;
70                 }else{
71                     loadingDiv.innerHTML = me.text;
72                     flag = true;
73                 }
74             },300);
75             return handler;
76         },
77         //关闭Loading
78         hide:function(){
79             clearInterval(handler);
80             var body = document.getElementsByTagName("body")[0];
81             var loadingDiv = document.getElementById('loadingDiv');
82             if(body && loadingDiv){
83                 body.removeChild(loadingDiv);
84             }
85             Loading.hideShadow();
86         }
87     }
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