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Basic Terms and Concepts


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case-sensitive
Noting capital and lowercase letters is important because JavaScript is ____
statements
Instructions in JavaScript are called ____
semicolon
Statements in JavaScript are separated by a ____ ( ; )
whitespace
Except for within strings, JavaScript ignores ___ characters. This includes spaces, tabs, and new line characters.
end
Always add a semicolon to the ____ of your statements.
// comment
Use this syntax to include a single-line comment in your script
/* comments */
Use this syntax to include multi-line comments in your script
declare
Always use the keyword var to ____ a variable
illegal name
If a variable does not start with an underscore (_), dollar sign ($) or letter it is an ____
ReferenceError
You will receive a ____ exception if you attempt to access an undeclared variable
undefined
If a variable is declared without a value, it is assigned the value ____.
boolean
A ____ is a JavaScript type that behaves as either true or false
false
In boolean contexts the values undefined and null behave as ____
not a number
The value NaN means ____
zero
In numeric contexts, null behaves as the number ___
NaN
In numeric contexts, undefined is toxic. It returns ____ no matter what the arithmetic operation being performed is.
square brackets
To declare an array, use the var keyword and assign it a pair of empty ____
functions
The fundamental building blocks of JavaScript programs are called ____. These must first be defined, and then can be used to perform tasks or calculate values.
objects
In JavaScript, collections of properties are known as ___. Think of them as containers for values.