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Extjs interview questions

Top Extjs interview questions and answers.

1. What is EXT.js ?

Ext.js is pure Javascript framework that is used for building interactive cross platform web applications such as desktopstablets, and smartphones using techniques like AjaxDHTML and DOM scripting. It provides pre-Integrated and tested UI Components such HTML5 calendargridspivot grid, D3 adaptertreeslistsformsmenustoolbars,panelswindows, and much more.
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2. List some features of Ext JS ?

Features of Ext Js

  • Pre-Integrated and Tested UI Components.
  • Rich Data Analytics.
  • Code compatibility of new versions with the older one
  • Sophisticated Data Visualization by supporting D3 js
  • A flexible layout manager helps to organize the display of data and content across multiple browsers, devices, and screen sizes
  • It is protocol agnostic, and can access data from any back-end source.
  • Customizable Built-In Themes

3. Which architecture is supported by Ext JS ?

Ext JS provides support for both MVC (Model view controller) and MVVM (Model View Viewmodel) application architectures.
Both of these architectural approaches share certain concepts and focus on dividing application code along logical lines

4. What is the latest stable version of Ext JS ?

As on August,2017 latest stable version of Ext JS 6.2.1.

5. List some advantages of using Ext JS.

  • Streamlines cross-platform development across desktops, tablets, and smartphones — for both modern and legacy browsers.
  • Increases the productivity of development teams by integrating into enterprise development environments via IDE plugins.
  • Reduces the cost of web application development.
  • Empowers teams to create apps with a compelling user experience.
  • It has set of widgets for making UI powerful and easy.
  • It follows MVC architecture so highly readable code.

6. Explain limitations of using Ext JS.

  • The size of library is large around 500 KB which makes initial loading time more and makes application slow.
  • HTML is full of
    tags makes it complex and difficult to debug.
  • According to general public license policy it is free for open source applications but paid for commercial applications.
  • Some times for loading even simple things requires few lines of coding which is simpler in plain html or Jquery.
  • Need quite experienced developer for developing Ext JS applications.

7. List out major Web browsers supported by Ext JS framework?

Below are list of browsers that are supported by Ext Js

  • Windows Internet Explorer version 6 and later
  • Mozilla Firefox version 1.5 and later (PC and Macintosh)
  • Apple Safari version 2 and later
  • Opera version 9 and later (PC and Mac)
  • Chrome10 and above

8. What are the different type of alert boxes available in Ext JS?

Different type of alert boxes in Ext JS are

  • Ext.MessageBox.alert();
  • Ext.MessageBox.confirm();
  • Ext.MessageBox.wait();
  • Ext.MessageBox.promt();

9. What is difference between ‘ext.js’ and ‘ext-all.js’ file?

ext-all.js: This file contains the entire Ext JS framework (used for Development & testing)

ext.js: This file contains the minimum Ext JS code (Ext JS base library)- used in Production.

10. List EXT JS components?

Ext JS has various UI components , we have list some most used components are:

  • Window
  • Form
  • Message Box
  • Progress Bar
  • Grid
  • Tool Tip
  • HTML Editor
  • Charts