I am currently redesigning my site, and as well as making it better looking and giving it new features, I also want to make editing it easier. Right now, it is all HTML and CSS, which means editing the HTML for some things can be rather annoying. Say for example if you added a new page to the site, at the moment you would have to change the site navigation menu individually on each page, (there are approx. 7 at the moment). What can I do here to make things easier, i.e. change one bit of code to sort out everything for every page. (Sort of like with CSS documents).
Would it be possible to script certain aspects of the site into a text file (e.g. The information needed for the site navigation menu) and then load it onto the page through javascript or php? once again, in the same sort of way as a CSS document, where you have one file affecting all 7 (or whatever) pages.