Making Decisions with Conditional Statements

Question 1

• Add a variable named answer and use the prompt() method to ask the question ‘What is the best programming language?’
• Add a conditional statement that opens an alert dialog box with the message “You are correct” when the answer contains the string ‘JavaScript’.
• Add an else clause to complete the conditional statement. Inside the else clause add another alert that says “JavaScript is the best language!”

Answer 1

var answer = prompt(“What is the best programming language?”);
if (answer === “JavaScript”) {
alert(“You are correct”);
} else {
alert(“JavaScript is the best language!”);
}

Question 2

T/F: You must add an else clause to a conditional statement.

Answer 2

False

Question 3

T/F: Is the following condition true or false?

( ‘javascript’ === ‘JavaScript’ )

Answer 3

False

Question 4

When a browser runs the code listed below, what will the user see?

var spaceShips = 0;

if (spaceShips === 0 ) {

alert(‘You lose!’);

} else {

alert(‘You are still alive!’);

}

Answer 4

The user will see an alert dialog box with the message “You lose!”

Question 5

T/F: Is the following condition true or false?

( ‘lion’ !== ‘zebra’ )

Answer 5

True

Question 6

T/F: Is the following condition true or false?

( ‘3’ === 3 )

Answer 6

False

Question 7

T/F: Is the following condition true or false?

( ‘lion’ > ‘zebra’ )

Answer 7

False

Question 8

Add a conditional statement that tests if the value in the variable a is greater than the value in variable b. If it is, pop up an alert with the message ‘a is greater than b’; also add an else clause that pops up the message ‘a is not greater than b’.

var a = 10;
var b = 20;
var c = 30;

Answer 8

if (a > b) {
alert(“a is greater than b”);
} else {
alert(“a is not greater than b”);
}

Question 9

Add a Boolean value to the condition in this conditional statement. Use a boolean value that will result in the message “This is true” appearing in an alert box.

if ( ) {
alert(‘This is true’);
} else {
alert(‘This is false’);
}

Answer 9

if ( true ) {
alert(‘This is true’);
} else {
alert(‘This is false’);
}

Question 10

Add a conditional statement that test to see if the isAdmin variable is true. If it is then open an alert with the message “Welcome administrator”.

var isAdmin = true;
var isStudent = false;

And an else if clause that tests to see if the isStudent variable is true. If it is then open an alert dialog with the message ‘Welcome student’.

Add a final else clause to this conditional statement so that if the isAdmin variable andisStudent variables are both false an alert opens with the message “Who are you?”

Answer 10

if ( isAdmin ) {
alert(‘Welcome administrator’);
} else if (isStudent) {
alert(‘Welcome student’);
} else {
alert(‘Who are you?’);
}

Question 11

Say you had a conditional statement with one if clause, two else if clauses and an else clause, each with its own code block. What is the maximum number of code blocks in that conditional statement that can run?

Answer 11

1

Question 12

Comment out the two lines of code below using JavaScript’s multi-line commenting syntax:

This isn’t part of the program It’s just a message to myself

Answer 12

/*

This isn’t part of the program It’s just a message to myself

*/

Question 13

After this code runs, what is the value of the variable itemToBuy?

var itemToBuy = ‘’;

var savings = 1000;

if ( savings > 500 ) {

itemToBuy = ‘Computer’;

} else if ( savings > 200 ) {

itemToBuy = ‘Phone’;

} else if ( savings > 0 ) {

itemToBuy = ‘Dinner’;

} else { itemToBuy = ‘…still saving…’; }

Answer 13

‘Computer’

Question 14

What does this condition evaluate to: true or false?

( true || false )

Answer 14

True

Question 15

Given the following code, what will appear in the browser’s console?

var x = 10;

var y = 20;

if ( x < 10 && y > 10 ) {

console.log(‘The condition passes.’);

} else {

console.log(‘The condition fails.’);

}

Answer 15

The condition fails.

Question 16

What does this condition evaluate to: true or false?

( true && false )

Answer 16

False

Question 17

Complete the code below so that either condition must be true for the alert message to appear:

if ( username === ‘’ _____ password === ‘’) {

alert(“Password or user name is missing”);

}

Answer 17

||

Question 18

Given the following code, what will appear in the browser’s console?

var ships = 10;

var score = 0;

if ( ships === 0 || score === 0 ) {

console.log(‘Game over.’);

} else {

console.log(‘Your score is zero.’);

}

Answer 18

Game over.

Question 19

Complete the code below so that both conditions must be true for the alert message to appear:

if ( loggedIn === true _____ level === ‘admin’) {

alert(“Access granted.”);

}

Answer 19

&&