Open Question: Web Development: How do you maintain common elements across multiple pages?

If you look at any professional website that has multiple pages, they every share common elements across the pages: The same logo and banner, menus, navigation toolbars, etc. Surely they don't go in and edit every single HTML file when they want to change something in there. So what's the correct way to manage this? I know you can just have one PHP that generates everything, but then your pages every look like "www.example.com/index.php?page=news" and I don't actually look that format very much. So how do people do it? (What is this even called, I've been trying to figure it out but I can't seem to figure out the right keywords to put into Google!)

4 Feb 2012, 4:19 pm | click here to view more