JavaScript Midterm Exam Flashcards
JavaScript is used to add ______ to web pages.
behavior
True or False?
Browsers begin executing JavaScript only when the entire page has loaded.
False
Add JavaScript to your page with the _____ element.
script
Use the _____ attribute in a tag to link to a separate JavaScript file.
src
JavaScript programs are made up of a series of ______.
algorithms
You can put your JavaScript in two places, ______ in the web page, or you can _____ to a separate file containing your JavaScript from your HTML.
right, link
One of the most common JavaScript statements is a variable declaration, which uses the _____ keyword to declare a new variable and the assignment operator, ____, to assign a value to it.
var, =
True or False?
JavaScript expressions compute values.
True
Three common types of expressions are ____, ______, and _____ expressions.
numeric, string, boolean
______ allow you to make decisions in your code.
if/else
____/____ statements allow you to execute code many times by looping.
while/for
Use ______ instead of alert to display messages to the Console.
console.log
True or False?
Console messages should be used primarily for sending messages to the users.
False
______ is the function provided for getting input from a user. If a user hits cancel instead of inputting data, _____ is returned from the function.
prompt, null
Code that continuously repeats itself without ever ending is called a(n) _______.
infinite loop
What is the ‘And’ Boolean operator in JavaScript symbolized by?
&&
______ is the function used in JavaScript for generating random numbers.
math.random
______ is the function that always rounds numbers down.
math.floor
Boolean operators always result in the values ____ or ______.
true, false
To get a false value from an OR operator (||) both values must be ______.
false
_______ is an English approximation of what your code should do.
psuedocode
What happens if you pass too many arguments to a function in JavaScript?
It ignores the extra arguments and runs perfectly fine.
True or False?
In JavaScript, the return type needs to be declared in the function signature.
False
A variable declared outside of a function is called a _______ variable.
global
A variable declared inside of a function is called a ______ variable.
local
The area of code in which you can use a variable is called the variable’s ______.
scope
If you forget to declare a variable inside of a function, its scope will be ______.
global
True or False?
JavaScript requires a function to be defined prior to the point of calling it in the code.
False
What method allows you to add a value to the end of an array?
.push();
An array item that has not been initialized will have the value: _______.
undefined
True or False?
In JavaScript, arrays may grow beyond their initialized size.
True
You identify an element in an array using its ______.
index
Which property of an array will tell you the number of items in the array?
.length
A ______ array occurs when there are undefined terms in the middle of an array.
sparse
______ is the process of organizing your code so that it is easier to read and maintain.
refactoring
_______ is looping through each item in an array to process each item.
iterating
The index of the first item in an array is _____.
0
The last index of an array is always one ____ than the length of the array.
less
JavaScript objects are a collection of _______ and _______.
Properties, Behaviors
When declaring an object, each property of an object has a name followed by a _____ then a value.
colon
When declaring an object, properties are separated from each other by a ______.
comma
To access a property of an object you use _______ notation.
dot
You can remove a property from an object using the _____ operator.
delete
Variables for objects hold a _______ to the object.
reference
_______ is a keyword that always refers to the object whose method is being called.
this
True or False?
A method is a function that has been assigned to a property name in an object.
True
You can iterate through an object’s properties using a _______.
for each
Object references are passed by _______, just like primitive variables.
values
DOM stands for __________.
Document Object Model
To find and access an element on a web page using its ID, use the _______ method of the _______ object.
getElementByID, document
To access or change the contents of an element you can alter its _________ property.
innerHTML
True or False?
ID’s on a web page must be unique.
True
True or False?
Classes on a web page must be unique.
False
______._______ is the object and property that will call a function only after the web page is fully loaded.
window.onload
Giving a function to an object that knows about an event so that it runs the code when the event happens is known as a _________ function or an event handler.
callback
To get the value of an attribute of an HTML element, use the ________ method.
getAttribute
To change an attribute of an HTML element, use the ________ method.
setAttribute
Anytime you call method to locate an element or attribute that does not exist, ______ is returned.
null
True or False?
The web browser creates the DOM for the web page.
True
True or False?
The innerHTML property holds only the text content of an element.
False
