IE中事件详细解析(二)

这次主要分析在不同的页面下，主要的DWebBrowserEvent2的发生时机。

我们先定义一个最简单的html

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
</head>
<body>
HELLO
</body>
</html>

这是，生成的序列如下所示：

[7012] DISPID_BEFORENAVIGATE2 paramCount:7, p0(VT_BOOL):0 p1(VT_BSTR):(null) p3(VT_BSTR):(null) p5(VT_BSTR):http://localhost/mylocalhost/purehtml.html p6(VT_DISPATCH) 
[7012] DISPID_DOWNLOADBEGIN paramCount:0, 
[7012] DISPID_NAVIGATECOMPLETE2 paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/purehtml.html p1(VT_DISPATCH) 
[7012] DISPID_DOWNLOADCOMPLETE paramCount:0, 
[7012] DISPID_DOCUMENTCOMPLETE:paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/purehtml.html p1(VT_DISPATCH)

可以看到，先触发的是BEFORENAVIGATE2，然后是DownloadBEGIN， NAVIGATECOMPLETE2， DOWNLOADCOMPLETE， DOCUMENTCOMPLETE。

对于一个引用js和css文件的html文件，源码如下：

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>Untitled Page</title>
    <script type="text/javascript" src="JsFunc.js"></script>
    <link rel="Stylesheet" type="text/css" href="cssBTN.css" />
</head>
<body>
<form>
    <input class="mybtn" type="button" value="dome" onclick="addd();" />
</form>
</body>
</html>

对于一个引用js和css文件的html文件，加载的顺序基本上是一样的。

[7012] DISPID_BEFORENAVIGATE2 paramCount:7, p0(VT_BOOL):0 p1(VT_BSTR):(null) p3(VT_BSTR):(null) p5(VT_BSTR):http://localhost/mylocalhost/withjscss.html p6(VT_DISPATCH) 
[7012] DISPID_DOWNLOADBEGIN paramCount:0, 
[7012] DISPID_NAVIGATECOMPLETE2 paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/withjscss.html p1(VT_DISPATCH) 
[7012] DISPID_DOWNLOADCOMPLETE paramCount:0, 
[7012] DISPID_DOCUMENTCOMPLETE:paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/withjscss.html p1(VT_DISPATCH)

包含多个frame的html文件如下：

<html xmlns="http://www.w3.org/1999/xhtml" >
<frameset cols="25%,50%,25%">
  <frame src="frame_a.htm" />
  <frame src="frame_b.htm" />
</frameset>
</html>

生成的事件序列如下

[7012] DISPID_BEFORENAVIGATE2 paramCount:7, p0(VT_BOOL):0 p1(VT_BSTR):(null) p3(VT_BSTR):(null) p5(VT_BSTR):http://localhost/mylocalhost/withFrames.htm p6(VT_DISPATCH) 
[7012] DISPID_DOWNLOADBEGIN paramCount:0, 
[7012] DISPID_BEFORENAVIGATE2 paramCount:7, p0(VT_BOOL):0 p1(VT_BSTR):(null) p3(VT_BSTR):(null) p5(VT_BSTR):http://localhost/mylocalhost/frame_a.htm p6(VT_DISPATCH) 
[7012] DISPID_BEFORENAVIGATE2 paramCount:7, p0(VT_BOOL):0 p1(VT_BSTR):(null) p3(VT_BSTR):(null) p5(VT_BSTR):http://localhost/mylocalhost/frame_b.htm p6(VT_DISPATCH) 
[7012] DISPID_NAVIGATECOMPLETE2 paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/withFrames.htm p1(VT_DISPATCH) 
[7012] DISPID_NAVIGATECOMPLETE2 paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/frame_a.htm p1(VT_DISPATCH) 
[7012] DISPID_DOWNLOADCOMPLETE paramCount:0, 
[7012] DISPID_DOCUMENTCOMPLETE:paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/frame_a.htm p1(VT_DISPATCH) 
[7012] DISPID_NAVIGATECOMPLETE2 paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/frame_b.htm p1(VT_DISPATCH) 
[7012] DISPID_DOCUMENTCOMPLETE:paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/frame_b.htm p1(VT_DISPATCH) 
[7012] DISPID_DOCUMENTCOMPLETE:paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/withFrames.htm p1(VT_DISPATCH)

IE分别为每个frame和主页面都生成一个BEFORENAVIGATE2 和NAVIGATECOMPLETE2 ，为每个frame均生成一个DOCUMENTCOMPLETE事件。

同时为主页面还生成DwonloadBEGIN和DOWNLOADCOMPLETE2 事件

对于带有一个iframe的页面：

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
</head>
<body>
hello
<iframe src="idx.html"></iframe>
 world
</body>
</html>

生成的序列如下：

[7012] DISPID_BEFORENAVIGATE2 paramCount:7, p0(VT_BOOL):0 p1(VT_BSTR):(null) p3(VT_BSTR):(null) p5(VT_BSTR):http://localhost/mylocalhost/iframeTest.htm p6(VT_DISPATCH) 
[7012] DISPID_DOWNLOADBEGIN paramCount:0, 
[7012] DISPID_BEFORENAVIGATE2 paramCount:7, p0(VT_BOOL):0 p1(VT_BSTR):(null) p3(VT_BSTR):(null) p5(VT_BSTR):http://localhost/mylocalhost/idx.html p6(VT_DISPATCH) 
[7012] DISPID_NAVIGATECOMPLETE2 paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/iframeTest.htm p1(VT_DISPATCH) 
[7012] DISPID_NAVIGATECOMPLETE2 paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/idx.html p1(VT_DISPATCH) 
[7012] DISPID_DOWNLOADCOMPLETE paramCount:0, 
[7012] DISPID_DOCUMENTCOMPLETE:paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/idx.html p1(VT_DISPATCH) 
[7012] DISPID_DOCUMENTCOMPLETE:paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/iframeTest.htm p1(VT_DISPATCH)

可以看出，对于单独的iframe，会生成一次befornavigate和NAVIGATECOMPLETE2，还有一个DOCUMENTCOMPLETE事件，并没有额外的Download相关事件发生。

带有动态生成iframe的页面：

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <script type="text/javascript" src="JsFunc.js"></script>
</head>
<body> 
 <input type="button" onclick="addFrame();" />
 <div id="MydID"></div>
</body>
</html>

js的代码如下：

function addFrame() {
    strFrame = "<iframe src='idx.html'></iframe>";
    ele = window.document.getElementById("MydID");
    ele.innerHTML = strFrame;
}

成的序列如下：

[7012] DISPID_BEFORENAVIGATE2 paramCount:7, p0(VT_BOOL):0 p1(VT_BSTR):(null) p3(VT_BSTR):(null) p5(VT_BSTR):http://localhost/mylocalhost/withJsGenFrame.html p6(VT_DISPATCH) 
[7012] DISPID_DOWNLOADBEGIN paramCount:0, 
[7012] DISPID_NAVIGATECOMPLETE2 paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/withJsGenFrame.html p1(VT_DISPATCH) 
[7012] DISPID_DOWNLOADCOMPLETE paramCount:0, 
[7012] DISPID_DOCUMENTCOMPLETE:paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/withJsGenFrame.html p1(VT_DISPATCH) 
/*  一下部分是在按了button之后，动态添加的序列 */
[7012] DISPID_BEFORENAVIGATE2 paramCount:7, p0(VT_BOOL):0 p1(VT_BSTR):(null) p3(VT_BSTR):(null) p5(VT_BSTR):http://localhost/mylocalhost/idx.html p6(VT_DISPATCH) 
[7012] DISPID_DOWNLOADBEGIN paramCount:0, 
[7012] DISPID_DOWNLOADCOMPLETE paramCount:0, 
[7012] DISPID_DOCUMENTCOMPLETE:paramCount:2, p0(VT_BSTR):http://localhost/mylocalhost/idx.html p1(VT_DISPATCH)

可以看出，按钮按下之后，会触发一次BEFORENAVIGATE2，但是没有与之对应的NAVIGATECOMPLETE事件。

这块儿要注意，动态生成iframe时，触发的DOCUMENTCOMPLETE所带的参数的pDisp是新iframe的IWebbrowser2接口，而这个新页面中没有frame，所以在这个事件中取到的frame的数量为零，但是主页面的frame的个数已经变成一了

梦想影吧

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原文地址：https://www.cnblogs.com/kwliu/p/2198055.html