Any web application requires interaction between the user and the user interface (UI). An application without interaction is not a true application; interactivity is a basic requirement.

The application that we built in the previous chapter does not allow interaction. It simply shows data, and the user cannot do anything with it (apart from look at it).

Suppose that we want to introduce a little interaction into the catalog application that we started building in the previous chapter. For example, perhaps we want to show an alert with the price of the product when the user clicks on the product area.

Provided that the product data includes the price, as in the following JSON object:

[
  {"code":"P01", 
   "name": "Traditional Merlot", 
   "description": "A bottle of middle weight...