Automatic Headers and Footers

Ok guys, I think I have a challenge for you (actually, I don't think this can be done, but I've been proven wrong every time I've made that assumption with php in the past, so I'll ask anyway). Here's the question: Is there a way to have php insert headers and/or footers into all of the html files in a given directory on the fly (not actually modifying the files)? And by this I mean take an existing valid HTML file and add headers and footers and end up with a valid HTML file. Now, before some of you get trigger happy and tell me to read the manual and point me to things like .htaccess, auto_prepend_file, google and the like, think about what I'm really asking.... It needs to insert the header after the -body- tag and put the footer in before the -/body- tag. It needs to do this without modifications to the HTML file. And yes, I understand that by default HTML files aren't going to be effected by the auto_prepend_file (since they aren't php files) - so it will require adding HTML to the list of php parsed file types. For instance, the goal would be to take the following code: -HTML- -Head- -Title-This is a test-Title- -body- Well, did it work? -/body- -/html- and convert it to this: -HTML- -Head- -Title-This is a test-Title- -body- -h1-This is a page header-/h1- Well, did it work? -h3-This is the footer-/h3- -/body- -/html- Can it be done? I don't think so, but I leave it up to your wiles to suggest a solution.... Thanks!!!