So you're loading a page that starts a php file executing. You then want to display the percentage that php file is complete, on your webpage. Is that correct?
This will definitely require Javascript - and likely something called xmlhttp. xmlhttp is a method for clients (read: browsers) to communicate with the server, after the page is loaded. You'll have to use that in order to get the updated % from the server. You can then put it in the title of your page with document.title as ~asgerhallas suggested.
Real programmers don't comment their code. If it was hard to write, it should be hard to understand.
You could just echo out the javascript to the browser whenever the percent changes, and then flush(); It works, I've used it from time to time. The HTML won't look good though.