Newbie question about Class

My question seems fundamental. I want to set a variable in one function in a class and then want to use the value in a second function. However, the functions are called a html page with two passes. Submit reloads the page and an if(...) calls the second function in the class. If I declare on the first run: $get_data = new edit_tag_file(); $edit_args= $get_data-> edit_prep(); The on the second pass, I'm stuck. I can't declare a new instance of "edit_tag_data". And, it appears the object is gone after I leave the page. Will the class structure do this for me or must I save the values in $GLOBAL or something? Thanks....