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Dojo Interview Questions and Answers

This page provides answers to frequently asked Dojo interview questions.

What is Dojo?

Dojo is an open-source JavaScript library. It simplifies the design and development of JavaScript/AJAX-based applications and websites. Think of it as a JavaScript toolkit for building cross-platform applications quickly.

Prominent Features of Dojo

Open-source JavaScript toolkit
Easy to learn
Creates highly interactive web applications
Offers widgets, utilities, and higher I/O abstraction
Licensed under BSD or AFL

History of Dojo

Dojo's development began in 2004 by Alex Russell and Dylan Schiemann. The initial code was written in September 2004, with the first release in March 2005.

Dojo's Basic Directory Structure

/index.html: The application entry point.
/app: The application module.
/app/main.js: The main script for the app module.

Dojo Architecture

Dojo's architecture comprises:

DojoX: Contains various unstable modules (difficult to integrate into Dojo or Dijit).
Dijit: A UI toolkit with modules for layout and widgets.
Dojo Core: Includes core and most non-visual modules.
Dojo Base: Contains automatically available functionalities.
Custom code: JavaScript code, HTML markup, and CSS.
Util: Build tools (optimization, style-checking, documentation, testing).

Advantages of Dojo

Dojo is a high-quality JavaScript toolkit with several advantages:

Loosely typed variables
Associative arrays
Objects and classes
W3C DOM support
Regular expressions

Use of Dojo DOM Functions

Dojo DOM functions create, delete, update, insert, and read page elements. They aim to improve cross-browser compatibility and simplify common operations.

Disadvantages of Dojo

Limited browser support
Difficult to hide Dojo code in commercial applications
High network bandwidth requirements
Limited documentation

What is Dijit?

Dijit is Dojo's UI library providing widgets for building web 2.0 GUIs with or without JavaScript. It can be used declaratively (via HTML attributes) or programmatically (through JavaScript).

Resources a Widget Contains

JavaScript file
HTML snippet

Features Provided by Dojo Widgets

Sortable tables
Dynamic charts
Menus
Tooltips
Tabs
2D vector drawings

Use of Modules in Dojo

Dojo modules use the Asynchronous Module Definition (AMD) format for easier debugging. A single reference accesses a module; properties on a single object expose multiple functions.

Asynchronous Module Definition (AMD)

AMD is a JavaScript specification defining an API for defining code modules and their dependencies, loading them asynchronously as needed.

Advantages of Dojo Charting

Presents statistical data clearly
Provides built-in themes and chart types
Flexible data representation
Works on most devices

Components of the Dojo Framework

Base
Dijit
Dojox
Util

Dojo vs. jQuery

Feature	Dojo	jQuery
Type	Framework	JavaScript library
Basis	HTML and JavaScript	Supports various web languages
Ease of Use	More complex	Easier to use
Network Bandwidth	Higher requirements	Works on higher and lower bandwidth
Use Cases	Larger websites and applications	Simpler websites

Dijit Layout Widgets

ContentPane
LinkPane
BorderContainer
TabContainer
SplitContainer
StackContainer
AccordionContainer

Conditions for Dojo/ready Callback

The dojo/ready module's callback function executes once these three conditions are met:

DOM is ready
All requested modules have finished loading
Higher-priority registered functions have completed

Ajax vs. Dojo

Ajax is a technology (Asynchronous JavaScript and XML), while Dojo is a JavaScript framework (like MooTools, jQuery, Prototype).

Use of Dojo in Adobe Integrated Runtime (AIR)

Dojo can be used in JavaScript-based Adobe AIR applications to meet AIR's security requirements. It includes an API viewer and a GUI for Dojo's build system, allowing the build system to run from within AIR without Java.