We explain to you differences between client-side and server-side, so you can see our below description.

Client-side Server-side
Client-side programming is run on the user’s computer. Server-side scripts are run on the server.
Examples of client-side programming are Javascript, HTML, and CSS. Some examples of server-side programming languages are C#, VB.NET, ASP, JSP, and PHP.
Client-side scripts are the limit of control and problems with operating systems and web browsers. Server-side programming can also be encrypted when users send form variables, protecting users against any back attempts.
Client-side script is the check the validation for use Javascript condition. Server-side scripts are the check the validation for use regular expression function.