Ext js interview questions

Ext.js is pure Javascript framework that is used for building interactive cross-platform web applications such as desktops, tablets, and smartphones using techniques like Ajax, DHTML and DOM scripting. It provides pre-Integrated and tested UI Components such HTML5 calendar, grids, pivot grid, D3 adapter, trees, lists, forms, menus, toolbars, panels, windows, and much more. Read more from https://www.sencha.com/products/extjs/

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

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

As on August 2018 latest stable version of Ext JS 6.2.1.

• 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.

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• 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.

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

Different type of alert boxes in Ext JS are

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

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.

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