why is this vbscript not fetching any value? - dom

Question

i am trying to write a vbscript that extracts the value from src attribute of an <img> tag that has a class attribute as this cs-poster-big
here is the code i have tried so far,
'Initializing object with Internet Explorer Application
set IE = WScript.CreateObject("InternetExplorer.Application", "IE_")
'setting properties of Internet Explorer to the newly create object
with IE
.Visible = 0
.navigate "http://www.roku.com/channels/#!details/12" 'INSERT WEBPAGE HERE
end with
'waiting for IE to load the page
'tried using IE.busy or IE.readyState <> 4 also
while IE.busy
wScript.sleep 500
wend
wScript.sleep 500
'getting all image tags from the webpage
Set imgTags = IE.document.getElementsByTagName("IMG")
'iterating through the image tags to find the one with the class name specified
For Each imgTag In imgTags
'tried imgTag.className also
If imgTag.getAttribute("class") = "cs-poster-big" Then MsgBox "src is " & imgTag.src
next
IE.quit
set IE= Nothing
MsgBox "End of script"
and it is not displaying any value but you can view the source of the page here and you can see it has an <img> tag with class cs-poster-big
i don't understand why it is not displaying in my script

Answer 1

Do While IE.Busy Or IE.ReadyState <> 4
WScript.Sleep 500
Loop
Wait until page is completely loaded.
EDIT - While this works in IE10, IE8 fails to locate the image. Not tested in other versions.
In this case, try to change your url to
http://www.roku.com/channels?_escaped_fragment_=details/12/netflix#!details/12/netflix
to avoid problems with the dynamic generate content.
Also, in IE8, code needs to be changed to get class name of the image. It should be
Do While IE.Busy Or IE.ReadyState <> 4
WScript.Sleep 100
Loop
Set imgTags = IE.document.getElementsByTagName("IMG")
For Each imgTag In imgTags
imgClass = imgtag.getAttribute("class")
If IsNull( imgClass ) Then
imgClass = imgTag.className
End If
If imgclass = "cs-poster-big" Then
MsgBox "src is " & imgTag.src
End If
Next
But not a solution, just a workaround.