To understand dynamic web pages you have to understand normal web pages. Typical non-dynamic web pages do not change every time the page is loaded into the browser, nor do they change if a user clicks on a button. The only change that you will see in static pages is to see them load and unload, like what happens when you click on a hyper link.

In a nutshell: static web pages (normal pages you build) always look the same and the content never changes unless you load a new page or you change the page yourself and upload the new version of the pages unto the server.

Dynamic pages do the opposite, they can change every time they are loaded (without you having to make those changes) and they can change their content based on what user does, like clicking on some text or an image. (I am not talking about loading a new page!)

One of the most common types of dynamic web pages is the database driven type. This means that you have a web page that grabs information from a database (the web page is connected to the database by programming) and inserts that information into the web page each time it is loaded. If the information stored in the database changes, the web page connected to the database will also change accordingly and automatically without human intervention.