How does web development work?

I suppose the best way to describe the difference between clientside and serverside is that the client side has no logic. So (ignoring what javascript can do) the client side can't make decisions, can't do ifs and elses, can't add up, etc etc The clientside merely renders what is given to it by the server - the browser normally being the thing doing the rendering. The clientside is stateless. It is a copy of the information created by the server, delivered (typically) by an HTTP request. One of these implementations of the information rendered is HTML. With javascript there is now the ability to change what has already been delivered to the client. And javascript can use logic - like the logic I described on the serverside - but the logic happens at the clientside. But until there is another HTTP request (e.g. via AJAX) then the changes to what is rendered in the browser only exist on the client - and only on that one single copy of the rendered content i.e. the one in the current browser - you aren't changing everyone else's view. Only another HTTP request would that any of that information be conveyed back to the server. So the serverside is where the logic happens. Normally with some access to a data store e.g. database, static files, XML. The reading, writing and interpreting of this data is what the server does. The decision maker. Frameworks are a bundle of code that has already been written by someone else to give you a head start so you aren't writing all the mundane stuff each time you start a project e.g. database operations. Look at frameworks like a toolbox. You have all your spanners there - these are the bits of code pre-written - so you don't have to forge a spanner each time you need to tighten a nut. You will still have to use the spanner - it won't tighten the nut on its own - but the point is the hard work of creating it is done. With regard to the word "dynamic" that is kind of a way of saying that the HTML being rendered isn't just the same HTML being "served" by the server each time, but instead some decision making is being done by your code before it sends the HTML to the client. So you could write a piece of code on the serverside that would never change e.g. fetch the posts from my forum database and return the HTML. That snippet in the code would be written once by you, but each time the database changes e.g. a new post is added, then the actual served HTML would be different. Look at "dynamic" as being the content rendered changing, but your severside code is never any different. Mastering the art of that last bit - creating the code that serves ever changing data most effectively/efficiently - is (in my view) what web development is. Hope this helps. (Caveat: this is a really basic view of what goes on)