Adding data submission to webpage

Hi there I'm thinking of hosting a program (more a webpage coded in html5) on a web server. I am modifying a free to use/modify/distribute program to get some feedback.
On completion, it gives the option to submit/email/print feedback. I would like to store these in a .txt/.xml document if possible. I can use the email option (which gives a laid out version of the results in the body of an email) but I was curious about how to get the submit option to work.
I read through threads here and people mentioned it requiring a server-side language like php but I'm still uncertain how to go about it. And I'm wondering if this would be a very involved piece of work when I can get feedback emailed to me? Just curious!