A condition in a conditional statement is really just a question with a yes or

no answer.

In JavaScript, we say that the condition evaluates to either true or false.

[SOUND] True and false have specific meaning in JavaScript.

They're called Booleans and along with strings and

numbers, they represent a third type of value in JavaScript.

Though they have an unusual name, Booleans are very simple.

In fact, a Boolean value can be only one of two possible values, true or false.

That's it.

Let's look at Boolean values in action.

You don't need to follow along in Workspaces for this.

I'm just going to use workspace to demonstrate these concepts.

You'll be doing plenty of programing in just a minute.

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In JavaScript programming, the two possible Boolean values are represented by

the keywords true and false.

Because all conditions return a true or false value,

we can actually see how these two keywords work by using them in this code.

If I type true inside the condition and

preview it, The condition is true is printed to the screen.

Now, if I type false inside the condition and preview it,

The condition is false is printed to the screen.

Notice that there are no quote marks around true or false.

They aren't strings.

They each represent a specific type of value,

a Boolean value, so don't put quotes around them.

You can assign a Boolean value to a variable just like you

can assign a string or number to a variable.

This is a common way to keep track of a certain condition throughout a program.

For example, let's see if we can use a Boolean value

in the random number guessing game.

You can follow along in Workspaces by opening the workspace on this page.

Open the script.js file.

Here's the program you created in the last video.

First, I'll add a new variable named correctGuess and

set it to the Boolean value false.

When the game begins, the player hasn't yet

guessed anything, so we'll say the guess is false.

The value of this variable will only change if

the player gets the correct answer.

So, next I'll remove the else clause here and

change the correct condition code block to set the variable to true.

So if the player guesses the correct number,

the correctGuess variable changes to true.

If the player guesses wrong, the variable isn't changed.

It stays what it was set at at the beginning, to false.

We can then test that variable and print out a message that matches the condition.

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This is a lot of code I know, but

this is a second conditional statement that we've added to the quiz.

We now have two conditional statements.

The second one checks to see if the value in the correctGuess variable is true.

If it is, then it writes a message telling the player he was correct.

If not, then a different message is printed,

telling the player what the random number was.

You can simplify this code a bit.

Remember that all conditions are either true or false.

That is, the test condition produces a Boolean value.

Because we're already storing either true or false in the correctGuess variable,

we don't need to use the equality operator at all.

We can get rid of it and just leave the Boolean variable there.

Let's step through this code line by line.

First, we create a variable with the Boolean false value.

Next, we create a random number.

We open a dialogue box and ask the user to supply a number.

Then the program tests the user's response.

If the user supplied the same number as the random number, then the correctGuess

variable is changed to true, meaning the player correctly guessed the answer.

If the player didn't, however, then the variable stays the same, false.

Then we have a new conditional statement.

If the value in correctGuess is true, then we write a winning message.

However, if the value is false, then we'll tell the player the number.

Let's see it in action.

Now, you might be wondering why do we go to all this bother.

The program worked just fine before adding this new variable.

Well, first it gave us a chance to start using Boolean values in our program.

But more importantly, it's going to make the program more flexible and

it'll let us respond to multiple conditional outcomes.

This is something you'll learn about in the next video.