Hack Facebook Chat History

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 :
 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 is done.
6) You can see full Chat History now.