I know something like this is possible, I’m pretty sure I’m just wording it wrong as I’ve been searching online for hours to no avail.
The same way an HTML page refers to the CSS file for a menu design, how can the HTML page also refer to a file (or the same CSS file if possible) to get the links information? So when I change the link information in that one file, it changes links on all HTML pages referring to it. Is this possible?
There is no simple way to do this. In general this happens server-side and is drawn from a database.
You CAN draw this data from a JavaScript file, using HTML templating without having to depend on a server. This may help.
http://net.tutsplus.com/tutorials/javascript-ajax/quick-tip-an-introduction-to-jquery-templating/