Load another site page into a DIV
I'm making my first site in a few years and have a sidebar menu and a content div. I am trying to have it so that if you click a menu link, the div contents are changed to whatever is in "home.php" or "about.php". When I used to make sites I'd wind up copying and remaking every page including the full-layout and the menu, but I really know that's not the way to go and I'm trying to focus on dynamic web development now.
I'm still not too sure if this is the way to go about it but I've spent the past week learning the basics of PHP and MySQL and now it's looking like I'll need some jQuery/AJAX? Any threads mentioning this though jump too far into it. Am I supposed to use PHP, jQuery, JS, AND AJAX? I'm trying to use innerHTML with JS but it looks like this isn't the best way to do it - I also cant' find an innerHTML method that specifically would load "myPage.php" into my content div. I'm just wondering if I'm even doing this the right way? In terms of industry standards, what is the accepted way to dynamically load content these days for a site with a few pages built in Notepad++? I just want to make sure I'm starting off on the right foot as this is the field I'd like to go into. I'm good with the basics of HTML and CSS, I just haven't looked too much at this side of things before.