Data binding is the process that establishes a connection between the application UI and data. So, data binding has two participants: the model (or the getter and setter properties of the model) and the UI element (to which the model is bound). In the case of AngularJS, the UI elements are the various DOM elements that make up our UI.

When the data changes its value, the UI elements that are bound to the data reflect changes automatically. Conversely, when the data shown in the UI element changes, the underlying model is updated to reflect the changes.