append a value to session variables

hi there , i am trying to develop a print cue system , where i append primary id's to a session variable, the data is then extracted from the database using the keys and formatted into a table and outputted to pdf to print , what i'd like to know of the best way of appending the values to a session variable i currently popup a new window with the id in the get variable add it to the session then close the window and refresh the main page to show the added result value , although this seems to be a little buggy it crashed an ie 5 browser and doing this very quickly on a few links crashed my ie6 browser , would sending to another page then header location bak be the better option ?