CodeHS JavaScript

Front

His name is Fred and he is less than 16 years old Options:
1. if (name = "fred" && age < 16 )
2. if (name === "fred" && age < 16 )
3. if (name = "fred" || age < 16 )
4. if (name === "fred" || age < 16 )

Back

if (name === "fred" && age < 16 )

Answer explanation

The correct choice is 'if (name === "fred" && age < 16 )' because '===' checks for both value and type equality, ensuring 'name' is exactly 'fred'. The use of '&&' ensures both conditions must be true.

Front

Repeat something 10 times Options: repeat 10, repeat { } until 10;, while (i = 10)

Back

for (var i=0; i<10; i++)

Answer explanation

The correct choice, 'for (var i=0; i<10; i++)', uses a loop to repeat an action 10 times. It initializes a counter, checks the condition, and increments the counter, making it suitable for this task.

Front

What is the symbol used for the INCREMENT operator in JS? Options: +, ++, =, ==

Back

++

Answer explanation

The INCREMENT operator in JavaScript is represented by '++'. It increases the value of a variable by one. The other options, such as '+', '=', and '==', serve different purposes in the language.

Front

Conditions return values of which data type? Options: Integer, boolean, floating-point, string

Back

boolean

Answer explanation

Conditions evaluate to true or false, making their return type boolean. Other types like integer, floating-point, and string do not represent the outcome of a condition.

Front

Loops in programming start counting from?

Back

0

Answer explanation

In programming, loops typically start counting from 0. This is known as zero-based indexing, which is common in many programming languages like C, Java, and Python. Therefore, the correct answer is 0.

Front

What symbol represents the or operator in JavaScript?

Back

||

Answer explanation

In JavaScript, the or operator is represented by the symbol ||. This operator returns true if at least one of the operands is true, making it distinct from the single pipe |, which is a bitwise operator.

Front

Arithmetic Operators
What is ++ ?

Back

increment

Answer explanation

The '++' operator is used in programming to increment a variable's value by one. Therefore, the correct answer is 'increment', as it directly describes the function of this operator.

Front

Which one of the following is NOT a logical operator? ||, &&, $$, !

Back

$$

Answer explanation

The correct answer is $$, as it is not a logical operator. The other options, || (logical OR), && (logical AND), and ! (logical NOT), are all standard logical operators used in programming.

Front

Generally speaking, what functionality does JavaScript provide when used as part of the "Web development trifecta"?

Back

Page manipulation capabilities and advanced interactivity

Answer explanation

JavaScript provides page manipulation capabilities and advanced interactivity, allowing developers to create dynamic and responsive web applications. This makes it essential in the web development trifecta alongside HTML and CSS.

Front

JavaScript is a scripting language. Scripting languages:

Back

interpret and automate a list of tasks that would otherwise be executed one-at-a-time by a person.

Answer explanation

Scripting languages are designed to interpret and automate tasks, allowing multiple actions to be executed quickly without manual intervention. This makes the first choice correct, as it captures the essence of scripting.