internet-explorer - 在不使用 sleep 的情况下检测网页何时加载

Question

我正在 Windows 上创建一个 VB 脚本，它在 IE 中打开一个站点。我想要什么:检测网页何时加载并显示一条消息。我通过使用 sleep ( WScript.Sleep ) 来实现这一点。网站加载时的秒数。但是，该站点在中途弹出用户名，密码。只有当用户输入凭据时，它才会完成页面加载。所以我不想在大约几秒钟内使用“ sleep ”，而是使用精确的函数或检测页面是否已加载的方法。我在线检查并尝试使用 Do While循环，onload , onclick功能，但没有任何作用。为简化起见，即使我编写了一个脚本来打开像 yahoo 这样的站点并进行检测，但在加载页面时显示消息“Hi”:如果不使用 sleep(WScript.Sleep)，它就无法工作。

Answer 1

尝试常规方法:

Set objIE = CreateObject("InternetExplorer.Application")
objIE.Visible = True
objIE.Navigate "https://www.yahoo.com/"
Do While objIE.ReadyState <> 4
    WScript.Sleep 10
Loop
' your code here
' ...

更新:这个应该检查错误:

Set objIE = CreateObject("InternetExplorer.Application")
objIE.Visible = True
objIE.Navigate "https://www.yahoo.com/"
On Error Resume Next
Do 
    If objIE.ReadyState = 4 Then
        If Err = 0 Then
            Exit Do
        Else
            Err.Clear
        End If
    End If
    WScript.Sleep 10
Loop
On Error Goto 0
' your code here
' ...

UPD2:您写道，当登录弹出窗口出现时，IE 断开连接，假设有一种方法可以捕获断开连接，然后再次获取 IE 实例。请注意，这是“异常编程” :) 我希望这会有所帮助:

Option Explicit
Dim objIE, strSignature, strInitType

Set objIE = CreateObject("InternetExplorer.Application") ' create IE instance
objIE.Visible = True
strSignature = Left(CreateObject("Scriptlet.TypeLib").GUID, 38) ' generate uid
objIE.putproperty "marker", strSignature ' tokenize the instance
strInitType = TypeName(objIE) ' get typename
objIE.Navigate "https://www.yahoo.com/"
MsgBox "Initial type = " & TypeName(objIE) ' for visualisation

On Error Resume Next
Do While TypeName(objIE) = strInitType ' wait until typename changes (ActveX disconnection), may cause error 800A000E if not within OERN
    WScript.Sleep 10
Loop
MsgBox "Changed type = " & TypeName(objIE) ' for visualisation

Set objIE = Nothing ' excessive statement, just for clearance
Do
    For Each objIE In CreateObject("Shell.Application").Windows ' loop through all explorer windows to find tokenized instance
        If objIE.getproperty("marker") = strSignature Then ' our instance found
            If TypeName(objIE) = strInitType Then Exit Do ' may be excessive type check
        End If
    Next
    WScript.Sleep 10
Loop
MsgBox "Found type = " & TypeName(objIE) ' for visualisation
On Error GoTo 0

Do While objIE.ReadyState <> 4 ' conventional wait if instance not ready
    WScript.Sleep 10
Loop

MsgBox "Title = " & objIE.Document.Title ' for visualisation

您可以从 DOM 中获取所有文本节点、链接等，如下所示:

Option Explicit
Dim objIE, colTags, strResult, objTag, objChild, arrResult

Set objIE = CreateObject("InternetExplorer.Application")
objIE.Visible = True
objIE.Navigate "https://www.yahoo.com/"

Do While objIE.ReadyState <> 4
    WScript.Sleep 10
Loop

Set colTags = objIE.Document.GetElementsByTagName("a")
strResult = "Total " & colTags.Length & " DOM Anchor Nodes:" & vbCrLf
For Each objTag In colTags
    strResult = strResult & objTag.GetAttribute("href") & vbCrLf
Next
ShowInNotepad strResult

Set colTags = objIE.Document.GetElementsByTagName("*")
arrResult = Array()
For Each objTag In colTags
    For Each objChild In objTag.ChildNodes
        If objChild.NodeType = 3 Then
            ReDim Preserve arrResult(UBound(arrResult) + 1)
            arrResult(UBound(arrResult)) = objChild.NodeValue
        End If
    Next
Next
strResult = "Total " & colTags.Length & " DOM object nodes + total " & UBound(arrResult) + 1 & " #text nodes:" & vbCrLf
strResult = strResult & Join(arrResult, vbCrLf)
ShowInNotepad strResult

objIE.Quit

Sub ShowInNotepad(strToFile)
    Dim strTempPath
    With CreateObject("Scripting.FileSystemObject")
        strTempPath = CreateObject("WScript.Shell").ExpandEnvironmentStrings("%TEMP%") & "\" & .gettempname
        With .CreateTextFile(strTempPath, True, True)
            .WriteLine (strToFile)
            .Close
        End With
        CreateObject("WScript.Shell").Run "notepad.exe " & strTempPath, 1, True
        .DeleteFile (strTempPath)
    End With
End Sub

还看 get text data

UPD3:我想在这里额外检查网页加载和初始化是否完成:

' ...
' Navigating to some url
objIE.Navigate strUrl
' Wait for IE ready
Do While objIE.ReadyState <> 4 Or objIE.Busy
    WScript.Sleep 10
Loop
' Wait for document complete
Do While objIE.Document.ReadyState <> "complete"
    WScript.Sleep 10
Loop
' Processing loaded webpage code
' ...

UPD4:在某些情况下，您需要跟踪是否在文档中创建了目标节点(通常，如果您在尝试通过 Object required 等访问节点时遇到 .getElementById 错误，则需要跟踪):

如果页面使用 AJAX(加载的页面源 HTML 不包含目标节点，像 JavaScript 这样的事件内容会动态创建它)，下面的页面片段中有一个示例，显示了它的外观。文本节点 5.99可能会在页面完全加载后创建，并且发生了对服务器的其他一些请求以显示额外数据:

...
<td class="price-label">
    <span id="priceblock" class="price-big color">
        5.99
    </span>
</td>
...

或者，如果您正在加载 e。 G。出现 Google 搜索结果页面并等待 Next 按钮出现(特别是，如果您在上一页调用了 .click 方法)，或者加载一些带有登录 web 表单的页面并等待用户名输入字段，如 <input name="userID" id="userID" type="text" maxlength="24" required="" placeholder="Username" autofocus=""> .

下面的代码允许额外检查目标节点是否可访问:

With objIE
    ' Navigating to some url
    .Navigate strUrl
    ' Wait for IE ready
    Do While .ReadyState <> 4 Or .Busy
        WScript.Sleep 10
    Loop
    ' Wait for document complete
    Do While .Document.ReadyState <> "complete"
        WScript.Sleep 10
    Loop
    ' Wait for target node created
    Do While TypeName(.Document.getElementById("userID")) = "Null"
        WScript.Sleep 10
    Loop
    ' Processing target node
    .Document.getElementById("userID").Value = "myusername"
    ' ...
    '
End With