Javascript Knowledge Pillars Prep Questions & Answers

JAVASCRIPT KNOWLEDGE PILLARS
PREP QUESTIONS & ANSWERS

When you call Screen.pixeldepth what does it return? - ANSWER-Number of bits used
to display one color
Which of the following statements accurately describe the concept of "NaN" in
JavaScript? - ANSWER-It is a property of the global object
NaN is a non-configurable, non-writable property
NaN indicates a failed operation on numbers
Which of the following are true about the JavaScript "Document" Object? - ANSWER-A
Document object represents the HTML document that is displayed in that window
The document contains the contents of the page
Which of the following accurately describes the "mouseout" event in JavaScript? -
ANSWER-It occurs when the mouse pointer is moved out of an element, or out of one
of its children
Which of the following statements about JavaScript basics is/are true? - ANSWER-
JavaScript is case-sensitive.
JavaScript is a single-threaded programming language.
What is the purpose of the Browser Object Model (BOM)? - ANSWER-To provide a way
for JavaScript to interact with the web browser
What are different types of Inheritance in JavaScript? - ANSWER-Classical Inheritance
Prototype Inheritance
What does the "Continue" Statement in JavaScript do? - ANSWER-It terminates the
execution of statements while iterating the loop
What is the purpose of the toLocaleString() method in JavaScript? - ANSWER-Returns
a string with the local representation of the date and time
_____ returns the number of options displayed in the selection list. - ANSWER-
select.length

, What is the definition of a function in JavaScript? - ANSWER-A block of code that
performs a specific task and returns a result
What is the difference between using single quotes and double quotes in JavaScript? -
ANSWER-Single quotes and double quotes can be used interchangeably to define
strings in JavaScript
Which of the following statements are true about JavaScript Objects? - ANSWER-To
create object classes, you should apply a function known as an object constructor that
defines the properties and methods associated with the object type
One object class can include objects defined in other classes
What is the purpose of the return statement in a function? - ANSWER-To specify the
value that should be returned from the function
Which of the following provides the most accurate definition of "Block Scope"? -
ANSWER-The variables can be scoped to the nearest pair of curly braces. Which
means they can't be accessed from outside that pair of curly braces
What are the categories that Non-Primitive datatypes are divided into? - ANSWER-
Object Array
What is the primary function of using "console.log()" in JavaScript? - ANSWER-To
debug and troubleshoot the issues
To display information and feedback to the user
Which of the following options can be used to determine the height of the screen in
JavaScript? - ANSWER-screen.height
screen.availHeight
Which of the following best defines "Global Scope" in JavaScript? - ANSWER-A scope
that is available throughout the entire program
Which of the following statements are correct about methods in JavaScript? - ANSWER-
Methods are actions that can be performed on objects
Method is a property containing a function definition
Methods are functions stored as object properties
What is returned by Screen.colordepth when invoked? - ANSWER-number of bits used
to display one color
Which of the following statements is correct about instance properties in JavaScript? -
ANSWER-These properties hold data that are specific to a given object instance