stopping popup windows in a web browser

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edward

(vbCity Leader)


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posts: 1481
since: Apr 8, 2001
from: Shropshire, England

http://www.vbcity.com/forums/topic.asp?tid=22075&highlight=beforenavigate&page=2

Hi,

As most 'unwanted' pop-ups occur during the 'OnLoad' event of the Body element, you can expand on cancelling the NewWindow by determining whether the document being loaded has completed:

Code:

Private Sub WebBrowser1_NewWindow2(ppDisp As Object, Cancel As Boolean)
  If WebBrowser1.Document.ReadyState = "interactive" Then
    ' Probable Script 'OnLoad'
    Cancel = True
    Debug.Print "New Window: Blocked"
  Else
    ' Check if an element has been activated
    If WebBrowser1.Document.activeElement Is Nothing Then
      ' Probable Script
      Cancel = True
      Debug.Print "New Window: Blocked"
    Else
      ' User selection likely
      Debug.Print "New Window: Allowed"
    End If
  End If
End Sub

Private Sub Form_Load()
  ' Ensure the WebBrowser is silent. Cancelled pop-ups often throw a script error:
  WebBrowser1.Silent = True
End Sub



Hope that helps smile

I'm not sure how you can get the NewWindow's target URL without allowing the new window to open.


One of the interesting things about the WebBrowser control is the number of ways you can achieve the same outcome. The expansion on the New Window routine is not elegant but hopefully it gives some indication of the range of possible reasons for a new window.

The code will redirect any Target="_blank" type navigation to the original window, but will allow user-activated links that are script based to open in a new window - this would probably be the point at which to implement a new form and RegisterAsBrowser code. An example is the 'Comment' link in a Microsoft KB article which uses javascript to open the target window.

Code:

Private Sub WebBrowser1_NewWindow2(ppDisp As Object, Cancel As Boolean)
Dim sLink As String
On Error Resume Next
If Not WebBrowser1.Document Is Nothing Then
  If Not WebBrowser1.Document.parentWindow.event Is Nothing Then
    If WebBrowser1.Document.parentWindow.event.Type = "MenuExtUnknown" Then
      
      ' CONTEXT MENU - NAVIGATE
      ' Get the URL of the source Element
      sLink = WebBrowser1.Document.parentWindow.event.srcElement.href
      Debug.Print "Context Menu: " & sLink
      If Len(sLink) > 0 Then
        ' Cancel New Window
        Cancel = True
        ' Force open in current window
        WebBrowser1.Navigate sLink
      End If
    End If
  Else
    If WebBrowser1.Document.activeElement Is Nothing Then
      ' PROBABLE OnLoad SCRIPT - BLOCK
      Debug.Print "Probable Script: Unknown"
      Cancel = True
    Else
    sLink = WebBrowser1.Document.activeElement.href
      If Len(sLink) > 0 Then
        If WebBrowser1.Document.activeElement.protocolLong = "Unknown Protocol" Then
          ' PROBABLE SCRIPTED LINK - ALLOW - *** SET NEW FORM
          Cancel = False
        Else
          ' LINK WITH EXTERNAL TARGET - NAVIGATE
          Debug.Print "External Link Target: " & sLink
          Cancel = True
          WebBrowser1.Navigate sLink
        End If
      Else
        ' UNKNOWN NEW WINDOW
        Debug.Print "Unknown Reason: -"
        Cancel = True
      End If
    End If
  End If
Else
  ' PROBABLE SCRIPT - BLOCK
  Cancel = True
End If
End Sub

The routine checks the protocol of the activeElement's link. Script based navigation will return 'Unknown Protocol'.

Hope that helps smile


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