controlgettext

For some reason, I didn't find anything about this function in the autoit forum (if there is anything, please leave a link).I'm interested in its usage, as the example for this function doesn't really help me.

I want something like this :

#code
Local $sText = ControlGetText("[CLASS:IEFrame]", "", 0)
MsgBox(0, "ControlGetText Example", "The control text is: " & $sText)
#endofcode

Here, one problem might be the ID (cause it's not "Edit1" and I used 0 because I thought it would work this way, and it kinda did, but the msgbox returned only some text, while I wanted it to return all text of the control, like all text of the webpage part - it is important for me to get the text using controlgettext).

Can you help me get the code right?( also I'm quite confused about the controlgettext, because it says I have to write the "The title of the window to access.", I don't know what I should use for CLASS : either   IEFrame    -> but the msgbox returns only a bit of info, either    Internet Explorer_Server    which is the class of the control, but that doesn't work, though I think this would have the msgbox display all text in the webpage, but this would be the CLASS of a control, not of a window and maybe this is why it doesn't work->if there is a function which I can use for getting the text of a control, please let me know. Again, I'm interested in getting all text in the webpage part and I don't know what's the right CLASS to use for this to work)

Thank you very much for your help.