I am starting to build a website. My basic layout plan looks something like this:

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*site name*

*navigation bar with links to the various areas of the site*




CONTENT




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Every page in the site will have the same title and navigation bar at the top, but with content, obviously, varying from page to page. The problem is that my site will consist of a lot of pages, and if I happen to change the design of my navigation bar at some point, I don't want to have to update every page. Is there some sort of script I can use that will allow each page to reference another document containing the script for the navigation section, without affacting its appearance in any way? (I certainly don't want to use frames... I want it to look completely normal, but allow , me to easily update just the top section.) Here's an example of the basic design idea: http://www.alternet.org/

I was going to say you could use frames but you asy you don't want to. An alternative way is to use Server Side Includes (SSI). I wrote a short article on it, which you can find here:
http://www.webdevinfo.com/articles/28

PHP is the perfect solution for you. Create a function called writeHeader() and writeNavBar() that each page calls from an included PHP file. If you want to make the change you mentioned, you change the one function and the functionality is immediately rendered to all pages.