js loading加载效果实现代码

protected void Page_Load(object sender, EventArgs e) 
{ 
ShowLoading(); 
System.Threading.Thread.Sleep(10000); 
ClientScript.RegisterClientScriptBlock(typeof(string), "", "<script>document.body.onload=function(){removeLoadMsg();}</script>"); 
} /// <summary> 
/// 显示页面正在加载中效果 
/// </summary> 
public void ShowLoading() 
{ 
StringBuilder s = new StringBuilder(); 
s.Append(" <script language=JavaScript type=text/javascript>\n"); 
s.Append(" var t_id = setInterval(animate,20);\n"); 
s.Append(" var pos=0;var dir=2;var len=0;\n"); 
s.Append(" function animate(){\n"); 
s.Append(" var elem = document.getElementById('progress');\n"); 
s.Append(" if(elem != null) {\n"); 
s.Append(" if (pos==0) len += dir;\n"); 
s.Append(" if (len>32 || pos>79) pos += dir;\n"); 
s.Append(" if (pos>79) len -= dir;\n"); 
s.Append(" if (pos>79 && len==0) pos=0;\n"); 
s.Append(" elem.style.left = pos;\n"); 
s.Append(" elem.style.width = len;\n"); 
s.Append(" }}\n"); 
s.Append(" function removeLoadMsg() {\n"); 
s.Append(" this.clearInterval(t_id);\n"); 
s.Append(" var targelem = document.getElementById('loader_container');\n"); 
s.Append(" targelem.style.display='none';\n"); 
s.Append(" targelem.style.visibility='hidden';\n"); 
s.Append(" }\n "); 
s.Append("</script>\n"); 
s.Append("<style>"); 
s.Append("#loader_container {text-align:center; position:absolute; top:40%; width:100%; left: 0;}\n"); 
s.Append("#loader {font-family:Tahoma, Helvetica, sans; font-size:11.5px; color:#000000; background-color:#FFFFFF; padding:10px 0 16px 0; margin:0 auto; display:block; width:130px; border:1px solid #5a667b; text-align:left; z-index:9999;}\n"); 
s.Append("#progress {height:5px; font-size:1px; width:1px; position:relative; top:1px; left:0px; background-color:#8894a8;}\n"); 
s.Append("#loader_bg {background-color:#e4e7eb; position:relative; top:8px; left:8px; height:7px; width:113px; font-size:1px;}\n"); 
s.Append("</style>\n"); 
s.Append("<div id=loader_container>\n"); 
s.Append("<div id=loader>\n"); 
s.Append("<div align=center>页面正在加载中...</div>\n"); 
s.Append("<div id=loader_bg><div id=progress> </div></div>\n"); 
s.Append("</div></div>\n "); 
//HttpContext.Current.Response.Write(s.ToString()); 
HttpContext.Current.Response.Write(s.ToString()); 
//HttpContext.Current.Response.Flush();