利用Response.Flush和iframe实现”服务器推”技术(续)
上一篇绍使用iframe实现”服务器推”，这个方式有个缺点在IE、FireFox会出现进度栏一直加载的状态，上一篇也介绍在IE的解决方法，建议先看下上一篇的内容。网上的说
http://www.zeitoun.net/articles/comet_and_php/start可以解决FireFox的问题，试了一下也只是IE下可以（也是使用htmlfile），FireFox还是会出现进度栏一直加载状态。
客户端代码：
1: <div id="content" style=" width:400px; height:200px; border:1px solid #FF0"></div>
2: <script type="text/javascript">
3: var comet = {
4: connection: false,
5: iframediv: false,
6:
7: initialize: function () {
8: if (navigator.appVersion.indexOf("MSIE") != -1) {
9:
10: // For IE browsers
11: comet.connection = new ActiveXObject("htmlfile");
12: comet.connection.open();
13: comet.connection.write("<html>");
14: comet.connection.write("<script>document.domain = '" + document.domain + "'");
15: comet.connection.write("</html>");
16: comet.connection.close();
17: comet.iframediv = comet.connection.createElement("div");
18: comet.connection.appendChild(comet.iframediv);
19: comet.connection.parentWindow.comet = comet;
20: comet.iframediv.innerHTML = "<iframe id='comet_iframe' src='Flush.aspx'></iframe>";
21:
22: } else if (navigator.appVersion.indexOf("KHTML") != -1) {
23:
24: // for KHTML browsers
25: comet.connection = document.createElement('iframe');
26: comet.connection.setAttribute('id', 'comet_iframe');
27: comet.connection.setAttribute('src', 'Flush.aspx');
28: with (comet.connection.style) {
29: position = "absolute";
30: left = top = "-100px";
31: height = width = "1px";
32: visibility = "hidden";
33: }
34: document.body.appendChild(comet.connection);
35:
36: } else {
37: // For other browser (Firefox...)
38: comet.connection = document.createElement('iframe');
39: comet.connection.setAttribute('id', 'comet_iframe');
40: with (comet.connection.style) {
41: left = top = "-200px";
42: height = width = "1px";
43: visibility = "hidden";
44: display = 'none';
45: }
46: comet.iframediv = document.createElement('iframe');
47: comet.iframediv.setAttribute('src', 'Flush.aspx');
48: comet.connection.appendChild(comet.iframediv);
49: document.body.appendChild(comet.connection);
50:
51: }
52: },
53:
54: // this function will be called from backend.php
55: getData: function (d) {
56: $('#content').append(d);
57: },
58:
59: onUnload: function () {
60: if (comet.connection) {
61: comet.connection = false;
62: // release the iframe to prevent problems with IE when reloading the page
63: }
64: }
65: }
66:
67: comet.initialize();
68:
69: </script>
70:
服务端代码：
1: protected void Page_Load(object sender, EventArgs e)
2: {
3: string startHTML = "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">" + Environment.NewLine
4: + "<html xmlns=\"http://www.w3.org/1999/xhtml\" >" + Environment.NewLine
5: + "<head>" + Environment.NewLine
6: + "</head>" + Environment.NewLine
7: + "<body>" + Environment.NewLine;
8:
9: startHTML += new String(' ', 1024) + Environment.NewLine;
10:
11: Response.Write(startHTML);
12: Response.Flush();
13:
14: string data = "<script type=\"text/javascript\">window.parent.comet.getData(\"{0}\");</script>";
17: Response.Write(string.Format(data, "开始发送数据：<br/>"));
18: Response.Flush();
19:
20: int index = 0;
21: while (true)
22: {
23: System.Threading.Thread.Sleep(2000);
24: if (index % 2 == 0)
25: {
26: Response.Write(string.Format(data, DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") + " 服务端发送数据<br/>"));
27: }
28: else
29: {
30: Response.Write(string.Format(data, DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") + " 无数据发送<br/>"));
31: }
32: Response.Flush();
33:
34: index++;
35: }
36: }
37: