How to GET or SET condition textbox inside WebBrowser

My plan is to get or set condition of textbox inside WebBrowser..

this is what iam trying :

If WBrowser.Document.GetElementById("searchbox").Focus = True Then
Dim XKeyboard as New FrmVKeyboard
XKeyboard.ShowDialog
Exit Sub
End If

But, this line make an error..

WBrowser.Document.GetElementById("searchbox").Focus = True

"Expression does not produce a value"

How can i get or set condition the textbox inside WebBrowser..