VBA / DOM-根据属性获取元素 [英] VBA/DOM - Get elements based on attribute

问题描述

Windows 7上的Excel2013。 XPath / Javascript / jQuery 超出范围。

Excel 2013 on Windows 7. XPath/Javascript/jQuery is out of scope.

我试图遍历页面中选定的 div 元素，即具有特定数据级属性的元素。

I am trying to iterate over select div elements in a page, namely elements that have a specific data-level attribute.

我当前的方法是与此类似，但我无法找到一种非手动方式来基于属性选择元素。我最接近的是这样的：

My current approach is similar to this, but I was unable to find a non-manual way to select elements based on attributes. The closest I came was something like:

With CreateObject("WINHTTP.WinHTTPRequest.5.1")
    .Open "GET", url, False
    .Send
    pHTML.body.innerHTML = .ResponseText
End With

Set eCollection = pHTML.getElementsByClassName("chapter").getElementsByTagName("div")

For i = 0 To eCollection.Length
    If eCollection(i).getAttribute("data-level") >= 0 Then ' Throw cake
Next i

虽然我确信它是可行的（如果不确定），但这种解决方案似乎不可行-optimize（如果仅对于循环将要结束的大小而言）是当我开始在这些元素中寻找特定元素和元素序列时。

This solution, while I am sure it is viable (if unelegant), seems sub-optimal if only for how big the loop is going to end up being when I start looking for specific elements and sequences of elements within these elements.

因此，我正在寻找一种执行以下操作的方法：

So I am looking for a way to do something like this:

For Each pElement In pHTML.getElementsByClassName("chapter").getElementsByTagName("div").getElementsByAttribute("data-level")
    ' Throw cake at the element
Next

我知道没有方法 getElementsByAttribute ，因此问题。

这里有我看不见的方法，还是我锁定手动迭代？

或者，如果我交换当前创建IE实例的方法，例如此答案，我是否可以方便地使用 querySelectorAll 最终得到类似于我上面概述的结果的东西？

Alternatively, if I swap my current approach for creating an IE instance, á la this answer, could I concievably use querySelectorAll to end up with something resembling the result I have outlined above?

推荐答案

对于其他任何人这样，外壳可以说是这样：

For anyone else coming this way, the outer shell, so to speak, can look like this:

Sub ScrapeWithHTMLObj(url As String, domClassName As String, domTag As String, domAttribute As String, domAttributeValue As String)
    ' Dependencies:
    ' * Microsoft HTML Object Library

    ' Declare vars
    Dim pHTML As HTMLDocument
    Dim pElements As Object, pElement As Object

    Set pHTML = New HTMLDocument

    ' Basic URL healthcheck
    Do While (url = "" Or (Left(url, 7) <> "http://" And Left(url, 8) <> "https://"))
        MsgBox ("Invalid URL!")
        url = InputBox("Enter new URL: (0 to terminate)")
        If url = "0" Then Exit Sub
    Loop

    ' Fetch page at URL
    With CreateObject("WINHTTP.WinHTTPRequest.5.1")
        .Open "GET", url, False
        .Send
        pHTML.body.innerHTML = .ResponseText
    End With

    ' Declare page elements
    Set pElements = pHTML.getElementsByClassName(domClassName)
    Set pElement = pElements(0).getElementsByTagName(domTag)

    ' Extract only elements with wanted attribute
    pEleArray = getElementsByAttribute(pElement, domAttribute, domAttributeValue)

    For Each e In pEleArray
        ' Do stuff to elements
        Debug.Print e.getAttribute(domAttribute)
    Next
End Sub

如果您选择这条路线，则还需要以下内容：

If you go this route, you'll also need something like this:

Function getElementsByAttribute(pObj As Object, domAttribute As String, domAttributeValue As String) As Object()
    Dim oTemp() As Object
    ReDim oTemp(1 To 1)

    For i = 0 To pObj.Length - 1
        'Debug.Print pObj(i).getAttribute(domAttribute)
        If pObj(i).getAttribute(domAttribute) = domAttributeValue Then
            Set oTemp(UBound(oTemp)) = pObj(i)
            ReDim Preserve oTemp(1 To UBound(oTemp) + 1)
        End If
    Next i

    ReDim Preserve oTemp(1 To UBound(oTemp) - 1)

    getElementsByAttribute = oTemp
End Function

显然，根据HTML树，您需要更改子元素中置零的元素。对于我在测试中使用的网站，此结构完美运行。

Depending on the HTML tree, you'll need to change which elements you zero in on in the sub, obviously. For the site I used in testing, this structure worked flawlessly.

示例用法：

调用ScrapeWithHTMLObj（ https： // somesite， chapter-index， div， data-level， 1）

它将输入第一个名为 chapter-index 的类，选择带有 div 标记的所有元素，最后提取包含该属性的所有元素数据级，值 1 。

It will enter the first class named chapter-index, select all elements with the div tag, and finally extract all elements containing the attribute data-level with value 1.

这篇关于VBA / DOM-根据属性获取元素的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！