Ext JS Interview Questions and Answers, Ext JS Interview Questions and Answers Freshers, Ext JS Interview Questions and Answers, Ext JS Interview Questions

Before getting on to the Ext JS interview questions, the student must know that the Ext JS is a continuously varying field which needs the students as well as professionals to upgrade their skills with the new features and knowledge, to get fit for the jobs associated with Ext JS. This post related to Ext JS Interview Questions and Answers, Ext JS Interview Questions and Answers Freshers, Ext JS Interview Questions and Answers, Ext JS Interview Questions will help you let out find all the solutions that are frequently asked in you upcoming Ext JS interview.

Over thousands of vacancies available for the Ext JS developers, experts must be acquaintance with all the component of Ext JS technologies. This is necessary for the students in order to have in-depth knowledge of the subject so that they can have best employment opportunities in the future. Knowing every little detail about Ext JS is the best approach to solve the problems linked with problem.

APTRON has spent hours and hours in researching about the Ext JS Interview Questions and Answers, Ext JS Interview Questions and Answers Freshers, Ext JS Interview Questions and Answers, Ext JS Interview Questions that you might encounter in your upcoming interview.  All these questions will alone help you to crack the interview and make you the best among all your competitors.

First of all, let us tell you about how the Ext JS technology is evolving in today’s world and how demanding it is in the upcoming years. In fact, according to one study, most of the companies and businesses have moved to the Ext JS. Now, you cannot predict how huge the future is going to be for the people experienced in the related technologies.

Hence, if you are looking for boosting up your profile and securing your future, Ext JS will help you in reaching the zenith of your career. Apart from this, you would also have a lot of opportunities as a fresher.

These questions alone are omnipotent. Read and re-read the questions and their solutions to get accustomed to what you will be asked in the interview. These Ext JS interview questions and answers will also help you on your way to mastering the skills and will take you to the giant world where worldwide and local businesses, huge or medium, are picking up the best and quality Ext JS professionals.

This ultimate list of best Ext JS interview questions will ride you through the quick knowledge of the subject and topics like Writing Code, Running Code, Foundation, Application Structure, Object Creation. This Ext JS interview questions and answers can be your next gateway to your next job as a Ext JS expert.

These are very Basic Ext JS Interview Questions and Answers for freshers and experienced both.

Q1: What is Ext JS?
A1: Ext JS stands for extended JavaScript. It is a JavaScript framework to develop rich UI web based desktop applications.

Q2: Explain features of Ext JS.

  • Customizable UI widgets with collection of rich UI such as Grids, pivot grids, forms, charts, trees.
  • Code compatibility of new versions with the older one.
  • A flexible layout manager helps to organize the display of data and content across multiple browsers, devices, and screen sizes.
  • Advance data package decouples the UI widgets from the data layer. The data package allows client-side collection of data using highly functional models that enable features such as sorting and filtering.
  • It is protocol agnostic, and can access data from any back-end source.
  • Customizable Themes Ext JS widgets are available in multiple out-of-the-box themes that are consistent across platforms.

Q3: What are the browser Ext JS supports?
A3: Ext JS supports cross browser compatibility, it supports all major browsers as –

  • IE 6 and above
  • Firefox 3.6 and above
  • Chrome10 and above
  • Safari 4 and above
  • Opera 11 and above

Q4: Difference between Ext JS and jQuery.
A4: Both the frameworks are quite different we can compare Ext JS and jQuery UI as Ext JS is full-fledged UI rich framework. But still Ext JS has much more components then jQuery UI.

Q5: Difference between Ext JS and Angular JS.

Parameter Ext JS Angular JS
Rich UI Ext JS provides rich UI options such as forms , grid, charts Angular JS does not provide rich UI inbuilt
Rich theme UI components Ext JS provides multiple themes inbuilt Angular JS does not provide Rich UI it has to be integrated with AngularUI, AngularBootstarp etc.
Cross browser compatibility Ext JS provide cross browser compatibility it works for almost all the browsers IE6+, FF, Chrome, Safari, Opera etc. Angular JS has to use third party library such as jQuery, jqLite for solving this purpose.
Automatic testing support Possible only with external tools Provides inbuilt.
Two way data binding In Ext JS 5 two way binding is included. It supports two way binding start from first version.
Performance Ext JS is comparatively heavier and slower. Angular JS is light weight framework than Ext JS
Build tools Ext JS uses Sencha cmd tool for builds Angular JS uses third party tools such as grunt.

Q6: What is xType in Ext JS?
A6: xType defines the type of Ext JS UI component, which is determined during rendering of the component. E.g. textField, Numeric, button etc.

Q7: What is vType in Ext JS?
A7: This is the validation type can be customized easily. Few vType provided by Ext JS are –
alphanumText – This returns false if the text entered has any symbol other than alphabate or numeric value.
emailText – This returns false, if text is not a valid email address.

Q8: Integration of Web development server-side frameworks with Ext JS?
A8: You can use Ext JS with other common Web development server-side frameworks, including PHP, the Java™ language, Microsoft® .NET, Ruby on Rails, and ColdFusion.

Q9: Extjs Ajax implementation?
A9: A typical Ext JS Ajax implementation: an HTML text field and button element that posts data in the text field to a Web server when the button is clicked.

Q10: What is method to Update the message box body text for MessageBox?
A10: updateText( [String text] ) : Ext.MessageBox

Q11: What is a widget?
A11: A widget is a tiny piece or component of functionality.

Q12: How to find no of records in a store?
A12: using store.getCount() : Gets the number of cached records.

store.getTotalCount() : Gets the total number of records in the dataset as returned by the server.

Q13: How many types of layout managers exist in extjs?what are they?
A13: Layouts fall under this package Ext.layout.*

Types of layouts:

Absolute Layout: This is a simple layout style that allows you to position items within a container using CSS-style absolute positioning via XY coordinates.

Accordion Layout: Displays one panel at a time in a stacked layout. No special config properties are required other than the layout.
All panels added to the container will be converted to accordion panels.

AnchorLayout: This type of layout is most commonly seen within FormPanels (or any container with a FormLayout) where fields are sized relative to the container without hard-coding their dimensions.

BorderLayout: Border layouts can be nested with just about any level of complexity that you might need.
Every border layout must at least have a center region. All other regions are optional.

CardLayout (TabPanel): The TabPanel component is an excellent example of a sophisticated card layout. Each tab is just a panel managed by the card layout such that only one is visible at a time
CardLayout (Wizard): You can use a CardLayout to create your own custom wizard-style screen.

FitLayout: A very simple layout that simply fills the container with a single panel.

FormLayout: FormLayout has specific logic to deal with form fields, labels, etc.FormLayout in a standard panel,

ColumnLayout: This is a useful layout style when you need multiple columns that can have varying content height.Any fixed-width column widths are calculated first, then any percentage-width columns specified using the columnWidth config

TableLayout: Outputs a standard HTML table as the layout container.you want to allow the contents to flow naturally based on standard browser table layout rules.
data, plus manip

Q14: What is vtype?
A14: The validations provided are basic and intended to be easily customizable and extended.

Few vtypes provided by extjs are as below:

emailText : String, The error text to display when the email validation function returns false

alphanumText : String, The error text to display when the alphanumeric validation function returns false

urlText : String, The error text to display when the url validation function returns false

Q15: Which architecture is supported by Ext JS?
A15: 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

Q16: Explain limitations of using Ext JS.

  • The size of the 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.
  • Sometimes 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.

Q17: What are the different type of alert boxes available in Ext JS?
A17: Different type of alert boxes in Ext JS are

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

Q18: List EXT JS components?
A18: Ext JS has various UI components, we have listed some most used components are:

  • Window
  • Form
  • Message Box
  • Progress Bar
  • Grid
  • ToolTip
  • HTML Editor
  • Charts

Q19: What is the latest stable version of Ext JS?
A19: As on August 2017 latest stable version of Ext JS 6.2.1.

Q20: What are the prerequisites for learning ExtJS?
A20: -First and most interest of self learning & work on open source libraries.

– Good knowledge on HTML, CSS, Javascript

-Drive through EXTJS API docs & practice samples

Q21: Explain the difference between ‘ext.js’ and ‘ext-all.js’ file?
A21: 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

Q22: What do you mean by Sandbox mode in ExtJS 4?
A22: -To run multiple versions of EXTJS side by side. Leverage your investments and migrate at your own place.

– To use Ext JS 4 in the sandbox mode, you need to import the ext-all sandbox files and the ext-sandbox.css file as well.

Q23: Explain the life-cycle of a component in ExtJS?
A23: The most important stages in the life cycle of every class based on Component:

1. Initialization:

-The config object is applied
-The base Component events are created
-The component is registered in ComponentMgr
-The initComponent method is called
-Plugins are loaded (if applicable)
-State is initialized (if applicable)
-The component is rendered (if applicable)

2. Rendering:

-The beforerender event is fired
-The container is set
-The onRender method is called
-The Component is “unhidden”
-Custom class and/or style applied
-The render event is fired
-The afterRender method is called
-The Component is hidden and/or disabled (if applicable)
-Any state-specific events are initialized (if applicable)

3. Destruction :

-The beforedestroy event is fired
-The beforeDestroy method is called
-Element and its listeners are removed
-The onDestroy method is called
-Component is unregistered from ComponentMgr
-The destroy event is fired
-Event listeners on the Component are removed

Q24: Do you have any advice for developers using ExtJS for the first time?
A24: ExtJS can be used by Web Application developers who are familiar with HTML but may have little or no experience with JavaScript application development. If you are starting to build a new web application, or you are revamping an existing application, then take your time to understand the basics of the library including.

Q25: How to access DOM element using EXTJS?
A25: The Element API is fundamental to the entire Ext library.
Using traditional Javascript, selecting a DOM node by ID is done like this:
var myDiv = document.getElementById(‘myDiv’);

Using Extjs:
Ext.onReady(function() {
var myDiv = Ext.get(‘myDiv’);

Q26: What is syntax for Extjs Button click event?
A26: Ext.onReady(function() {
Ext.get(‘myButton’).on(‘click’, function(){
alert(“You clicked the button”);

Q27: Write syntax for MessageBox show() method?
A27: Ext.MessageBox.show({
title: ‘Paragraph Clicked’,
msg: ‘User clicked on Paragraph’,
buttons: Ext.MessageBox.OK,
animEl: paragraph

Q28: How to handle event for a extjs component?
A28: 1) Using listeners config object.
For ex for grid events : listeners: {rowclick: gridRowClickHandler,rowdblclick: gridRowDoubleClickHandler}

2) Using addListener( String eventName, Function handler, [Object scope], [Object options] ) : void
Appends an event handler to this component

3) Using on( String eventName, Function handler, [Object scope], [Object options] ) : void
Appends an event handler to this element (shorthand for addListener)
For ex: store.on( “datachanged”, function( store ){ ….. });

Q29: How Ext JS 6 can be used for both desktop and mobile applications?
A29: Ext JS 6 has toolkit package with which it can include visual elements of both the frameworks (Ext JS and Sencha Touch).

It can be added as –

‘toolkit’: ‘classic’, // or ‘modern’

If toolkit is classic it includes Ext JS desktop application framework.

And if toolkit is modern then it includes sencha touch mobile application framework.

Q30: Write the base classes for form, grid, chart, panel & tree.

  • Base class for Grid – Ext.grid.GridPanel
  • For form – Ext.form.Panel
  • For panel – Ext.panel.Panel
  • For chart – Ext.chart.Chart
  • For tree – Ext.tree.Panel

Ext JS Conclusion Interview FAQs

We know the list of Ext JS Interview Questions and Answers, Ext JS Interview Questions and Answers Freshers, Ext JS Interview Questions and Answers, Ext JS Interview Questions is overwhelming but the advantages of reading all the questions will maximize your potential and help you crack the interview. The surprising fact is that this Ext JS interview questions and answers post covers all the basic of the Ext JS technology and you have to check out the FAQs of different components of Ext JS too.

However, you will be asked with the questions in the interview related to the above mentioned questions. Preparing and understanding all the concept of Ext JS technology will help you strengthen the other little information around the topic.

After preparing these interview questions, we recommend you to go for a mock interview before facing the real one. You can take the help of your friend or a Ext JS expert to find the loop holes in your skills and knowledge. Moreover, this will also allow you in practicing and improving the communication skill which plays a vital role in getting placed and grabbing high salaries.

Remember, in the interview, the company or the business or you can say the examiner often checks your basic knowledge of the subject. If your basics is covered and strengthened, you can have the job of your dream. The industry experts understand that if the foundation of the student is already made up, it is easy for the company to educate the employ towards advance skills. If there are no basics, there is no meaning of having learnt the subject.

Therefore, it’s never too late to edge all the basics of any technology. If you think that you’ve not acquired the enough skills, you can join our upcoming batch of Ext JS Training in Noida. We are one of the best institute for Ext JS in noida which provide advance learning in the field of Ext JS Course. We’ve highly qualified professionals working with us and promise top quality education to the students.

We hope that you enjoyed reading Ext JS Interview Questions and Answers, Ext JS Interview Questions and Answers Freshers, Ext JS Interview Questions and Answers, Ext JS Interview Questions and all the FAQs associated with the interview. Do not forget to revise all the Ext JS interview questions and answers before going for the Ext JS interview. In addition to this, if you’ve any doubt or query associated with Ext JS, you can contact us anytime. We will be happy to help you out at our earliest convenience. At last, we wish you all the best for your upcoming interview on Ext JS Technology.