cache and session_start

Here is the situation: Two pages #1 and #2 #1 has a text box and submit #2 does something with the info put into the text box When I input text into box on #1, press submit to go to #2, than click BACK button on the browser, Text that I originally typed into the box is still in there on #1. Thats what I need!!! If I add session_start(); to the #1 this will not be true anymore. Once I am on #2, if I press BACK on the browser, #1 box will be empty. Any ideas why and how I Can prevent that? Besides registering this text as a session variable or using cookies. Something with browser cache? Thank you, Oleg Timofeyev