Basic input concepts (prompt overview) in Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the prompt() function do in JavaScript?

It shows a dialog box that asks the user to enter some text. The text entered is returned as a string.

beginner

How do you store the user's input from prompt() in a variable?

You assign the result of <code>prompt()</code> to a variable, like <code>let name = prompt('Enter your name');</code>.

beginner

What type of data does prompt() return?

It always returns a string, even if the user types numbers.

intermediate

How can you convert the string input from prompt() to a number?

Use functions like Number(), parseInt(), or parseFloat() to convert the string to a number.

intermediate

What happens if the user clicks 'Cancel' in a prompt() dialog?

The prompt() returns null, which means no input was given.

What does prompt('Enter age:') return if the user types 25?

A undefined

B '25' (a string)

C null

D 25 (a number)

prompt() always returns a string, so typing 25 returns '25'.

How do you save user input from a prompt into a variable called userName?

A userName = prompt('Enter name');

B prompt('Enter name') = userName;

C let prompt = userName('Enter name');

D var userName = alert('Enter name');

You assign the result of prompt() to the variable like userName = prompt(...).

What value does prompt() return if the user clicks 'Cancel'?

A null

B undefined

C An empty string ''

D 0

Clicking 'Cancel' returns null to indicate no input.

Which function converts a prompt's string input to a number?

A prompt()

B alert()

C parseInt()

D console.log()

parseInt() converts strings to integers.

If you want to ask the user for their favorite color, which code is correct?

A prompt('What is your favorite color?') = color;

B console.log('What is your favorite color?');

C alert('What is your favorite color?');

D let color = prompt('What is your favorite color?');

Use prompt() and assign it to a variable to get user input.

Explain how the prompt() function works and how to use it to get user input.

Think about how you ask a friend a question and get their answer.

Describe what happens when a user clicks 'Cancel' in a prompt dialog and how to handle it.

Cancel means the user decided not to answer.