To use this Trick follow the simple steps
given below
1) Open Friends profile.
2) Right Click on the Poke and Select Copy
Link Location. Now we have the ID in our
Clipboard.
3) This will exactly look like span
style=”color: red;”> http://
www.facebook.com/ profile.php?id=XYZ
( where XYX can be any numbers and this XYZ
is nothing but the ID).
4) Now in the Address Bar type ”
javascript:Chat.openTab (XYZ) ” (without
qoutes) and press Enter.
5) Now it’s done.
6) You can see full Chat History now.
Enjoy..!!!