Where client side programming is focused on mainly JavaScript at this point, server side programming has several popular programming languages including, but not limited to, PHP, ASP.Net, Ruby, Python, Java, and many more.
The languages that are picked have to deal with what the developer is comfortable with, what the server is capable of handling, and the type of work that is being done. Regardless of the language used the end result is a program which generates HTML compliant output that can be sent to the browser to be consumed by the end user’s web browser.
Client side programming is limited to the information that is sent to the end users browser. However, server side programming can have access to a lot more information, because the servers can collect, store, and use that information.
Consider a website like Amazon which tracks not only what you purchase, but what you look at, and what products you compare to other products before making a purchase. They can use that information to recommend other products to purchase to others.
Likewise, you might have products recommended to you based upon similar products that you have looked based upon people who have similar buying patterns with you.
Similarly, social media websites will track all the information that a user likes, comments on, etc, and recommend additional friends, display certain content, and even change what types of ads to display to you.
Smaller websites can still use data, just not as much as it. They can reference data stored on the server and change a page. This could be simple like displaying information on products, users, etc.
A server side language can take user information that is entered into the website and modify the result based upon that information.
With modern frameworks that pull data from the server to the client, the server side languages would interact with the client, but in reality, they just submit data to the client side so they work together in a loose coupling methodology.
Server Side Programming for a Website was originally found on Access 2 Learn