Client-side logic executes on the client machine; for example, data validation that's been implemented using client-side code runs in the browser. Dynamics 365 CE allows us to use client-side language tools such as JavaScript's jQuery to implement client-side logic. We can use client-side code on entity forms to implement data validation or to display data from other entities. To implement client-side logic for entities, first, we need to understand the client-side API object model. We can do so using the following diagram:

As shown in the preceding diagram, we have four main contexts that come under the client API object model root.