passing array through $PHP_SELF

I have a page that selects students from a mysql table who meet a certain requirement. Those who meet the requirement have a check box variable that is "checked." (The other students have the check box, but it is unchecked.) The "checked" student id numbers are sent to the next PHP page. That page allows the user to edit the text of a message that will be sent to each of the students "checked" on the previous page. Up to this point I'm fine. I can pass the array of student ids and read them on the other page. What I want to do is use $PHP_SELF to allow the user to preview the letter after editing. My initial tries haven't worked. If I just submit $PHP_SELF the student id array disappears. When I attempt to create a "hidden" form field I get the message: Parse error: parse error, expecting T_STRING' or T_VARIABLE' or `T_NUM_STRING' Right now I have the book open to implode and explode, figuring I can translate the array and then pass it back and forth, but that seems rather inelegant. Is there a "simple" way to pass an array when using $PHP_SELF to reload a page? TIA John Hughes