This book is an exploration of Ext JS, which is a JavaScript framework. It begins by giving the user a brief overview of Ext JS. An explanation on what it is has been given as well as where it is used. The next step is a guide for you on how to create a sample app in Ext JS 6. You are guided on how to create a login app. The app involves both the login and logout functionalities. The components making the user interface for this app are discussed and then added to the app. These include the buttons, the text fields, and the necessary labels. The process of authenticating the credentials provided by the user is discussed, putting you in a position to do it. The functionalities, both login and logout, are handled in the app. You will learn how to use the various functions which can be used for doing these tasks. The various components which are used in Ext JS 6 are explored in detail. The first component to be discussed is the grids. You will learn how to create these in Ext JS 6. The two types of editing, that is, cell and row editing are examined, as well as how to enable these in your application. Trees are also discussed, which are used for holding data hierarchically. You will learn how to add nodes to your tree, along with the process of loading a tree, either the entire tree or part of it. The following topics are discussed in this book: - A Brief Overview - Creating a Login System - Components