how to make the php page always newest when clicking 'back' botton in browser?

Hi,I meet a problem when I am developing. I am developing php base on other programer's php code . I must make the php page always newest when clicking 'back' botton in browser(because that programer using javascript: history.go(-1)), I try sent header() to disable cach,but seems to not works: my development show below: I have two page: page1 and page2 , on page1 I have a form which used to send parameter to page2, when I submit this form ,the URL change to page2 ,page2 use php code to deal with parameter and date submitted by form on page1 , then page use javascript: history.go(-1) to return page1 . and page1 must show newest information . I think it maybe not php questtion ,maybe I shoud insert some javascript code into page1 somewhere,but I don't know what to . Could somebody help me , thank you very much.