Which parts of Lightning Components are server-side and which are client-side?

Hii Anjali,

In a lightning component, the client side is a component page and the java script controller and the server side is the apex controller and the databases. Lightning component has an  advantage over the visualforce page in that it provides the java script controller over the client side.

The lightning component framework is a client-side framework, tightly coupled with the Salesforce server technology.

Lightning Components can use JavaScript on the client side and Apex on the server side. You don’t have to spend your time optimizing your apps for different devices as the components take care of that for you.

Thanks