javascript - Powershell搜索自动化-GetElementbyID不会返回使用Javascript创建的控件的值

Question

我正在进行一个项目，以在县网站上自动搜索税收记录。最终，我希望能够为Powershell提供ID编号列表，并使其返回所有这些编号的结果。到目前为止，我的代码在这里:

#Open IE and go to www.gastontax.com
$ie = new-object -com "InternetExplorer.Application"
$ie.navigate("http://www.gastontax.com/")
$ie.visible = $true

#Yield the script while the page is loading
While ( $ie.busy -eq $true){
[System.Threading.Thread]::Sleep(200)
}

#Set the document and the frames
$doc = $ie.document
$frames = $doc.frames

#Accept the notification
$btn = $doc.getElementByID("ctl00_Tax_btnAccept")
$btn.click()

#Yield the script while the page is loading
While ( $ie.busy -eq $true){
[System.Threading.Thread]::Sleep(200)
}

#Create the drop-down search parameters
$taxyear = "All"
$status = "Unpaid"
$searchtype = "Both"
$searchparam = "Parcel Number"
$searchtext = "XXXXXX"

#Set the drop-down search parameters
$doc.getElementbyID("ctl00_Tax_drpTaxYear").value = $taxyear
$doc.getElementbyID("ctl00_Tax_drpStatus").value = $status
$doc.getElementbyID("ctl00_Tax_drpSearchType").value = $searchtype
$doc.getElementbyID("ctl00_Tax_drpSearchParam").value = $searchparam

#Create the parcel name parameter
$doc.getElementbyID("ctl00_Tax_txtSearchParam").value = $searchtext

$btn2 = $doc.getElementByID("ctl00_Tax_btnSearch")
$btn2.click()

但是，每当我尝试设置控件的值时，对于每条getElementbyID行我都会收到以下消息:

The property 'value' cannot be found on this object. Verify that the property exists and can be set.

我注意到，我要查找的值-“ctl00_Tax_drpTaxYear”，“ctl00_Tax_drpStatus”等-直到我点击欢迎页面上的按钮(在$ btn.click( ))。这可能与Powershell抛出的错误有关吗？如果是这样，我将如何解决？

谢谢!

Answer 1

我只能将其与涉及战略性地切换IE(Internet Explorer)可见性的黑客一起使用，这似乎是DOM在$ie.Document中完全体现的必要条件(请参见下面的源代码中的注释)。

该骇客似乎可以在装有IE 11的Windows 10机器上可靠地运行，但可以使用YMMV。

通常:

Internet Explorer COM Automation interface已过时，因此值得考虑替代方案，例如Edge's WebDriver support(与may become a W3C standard完全不同的技术)。

坚持使用IE COM对象，如果改为使用DOM-related events，则可能不需要黑客，但我不确定PowerShell中是否支持它们。

# Helper function for wating until a condition is true.
function await([scriptblock] $sb) {
  while (-not (& $sb)) { Start-Sleep -Milliseconds 200 }
}

$ie = new-object -com "InternetExplorer.Application"
$ie.navigate("http://www.gastontax.com/")

# Wait until the page has finished loading.
await { $ie.ReadyState -eq 4 }

# Click the "Yes, I accept" button.
$ie.document.getElementById("ctl00_Tax_btnAccept").click()

# !! HACK (part 1 of 2):
# !! Delaying making IE visible until here seems to be the only way
# !! to get the new DOM to be at least *partially* reflected in $ie.document.
$ie.visible = $true

# Wait until the page has finished loading.
await { $ie.ReadyState -eq 4 }

# !! HACK (part 2 of 2):
# !! Inexplicably, another toggling of visibility is what it takes for *all* 
# !! elements in the new DOM to be accessible via $ie.Document.
$ie.visible = $false
$ie.visible = $true

#Create the drop-down search parameters
$taxyear = "All"
$status = "Unpaid"
$searchtype = "Both"
$searchparam = "Parcel Number"
$searchtext = "XXXXXX"

#Set the drop-down search parameters
$doc = $ie.document
$doc.getElementById("ctl00_Tax_drpTaxYear").value = $taxyear
$ie.document.getElementById("ctl00_Tax_drpStatus").value = $status
$ie.document.getElementById("ctl00_Tax_drpSearchType").value = $searchtype
$ie.document.getElementById("ctl00_Tax_drpSearchParam").value = $searchparam

#Create the parcel name parameter
$ie.document.getElementById("ctl00_Tax_txtSearchParam").value = $searchtext

$ie.document.getElementById("ctl00_Tax_btnSearch").click()