Question:What are ExtJS Widgets? 

These include components such as a messages box, grid, and window and everything else that serves a particular user interface. Example: Calendar, MsgBox, Grid Panel etc.

Question:What do the following files do in ExtJS?
a) Ext-all.css
b) Ext-base.js
c) Ext-all-debug.js/ext-all.js 

a) Ext-all.css Ans: A style sheet file that controls the look and feel of Ext widgets.      b) Ext-base.js Ans: This file provides the core functionality of Ext.      c) Ext-all-debug.js/ext-all.js
Ans: All of the widgets live in this file. The debug version is used for development, and then swapped out for the non-debug version for production.

Question:What is localization? Write down three scenarios for localization that require three separate approaches. 

The localization is the process of localizing native culture setting correctly according to the country and region such as language, date-time etc.

There are three scenarios for localization that require three separate approaches in ExtJS:
a) English only
b) A single language other than English
c) Multiple languages

Question:What is JSON? How does JSON work? 

JSON (JavaScript Object Notation), is a lightweight text-based open standard designed for human-readable data interchange. It is derived from the JavaScript scripting language for representing simple data structures and associative arrays, called objects. Despite its relationship to JavaScript, it is language-independent, with parsers available for most languages.

Question:What is a config object in ExtJS? What to remember when working with a config object? 

config objects are just ways of structuring data so that it can easily be read by programming languages. Here are some key thing to remember:
 1.curly brackets warp around our whole record set.
 2. Each record consists of a set of name/value pair.
 3. The records values can contain any type of data.
 4. Square brackets identify an array.

Question:
What’s a dirty cell?
 

A field that has been edited and its value changed are considered to be dirty cell until the data store is told otherwise. This ‘dirty’ value has been saved to a temporary data store.

Question:What are layouts, regions, viewports, and panels? Draw and label the border and nested layout regions. 

Layouts: A layout turns forms, grids and other widgets into a true web application. The most widely-used layout styles can be found in operating systems such as Microsoft’s Window.Regions: A viewport has regions that are laid out in the same way as a compass, with north, south, east, west regions.Viewports: A viewport is a special panel-like component that encloses the entire layout, fitting it into the whole visible area of our browserPanels: Panels are a wider side bar as a container. It may usually be located at left, right, top, bottom in the view port.

Question:What are built in validation and custom validation in ExtJS? Show an example of Custom validation? 

Built in validation can be used to validate and restrict user input and report back error messages. It will work in just about any scenario because it uses regular expressions to do the grunt work. Four built in validation is available in ExtJS: email, url, alpha, alphanum.

Custom validation means to create own our vtype that is needed to add it to the vtype definitions. Each definition has a value, mask, error text and a function used for testing.</p>
Ext.form.Vtype[‘nameMask’]=/[A-Za-z\-]/;

Question:
What is Tree in ExtJS?
 

The Ext JS tree is built on top of the Component model, Which underlies the whole Ext JS framework.We can edit data directly in the tree, changing labels and item positions, or we can modify the appearance of the overall tree.

Question:Define Ext.onReady()? 

This function makes sure that our document is ready to be thrashed out.
Ext.onReady(function({
});