Ok basically I am building a simple web application where users can create accounts and log in and post bits of data that pertain to the project I am doing. I am using PHP scripts and logging data to an SQL database and I would like to make my entire site in one single script if this is a reasonable thing to do. I am concerned however about the $_POST data variable still holding the same information each time the page is refreshed... for example, I was testing my registration page and after I submitted some data from form fields, it seems like the data is still there in the $_POST variable since if I refresh the page the data gets sent again and I end up with another entry in my database. I know this is a rough explanation of what I am doing but my main point is that I want to know if it is best to just send data to an external script from a regular html page with a form, or if I can safely do it all in one single script.
Thanks