Essential JavaScript

Empty Variables

Earlier, we declared a variable with a value like this.

var x = 10;

We can also declare a variable without assigning a value.

Try running this in the editor:

var x;

In this case, the value of the variable is undefined.

Now try this:

var x = 5;

This time we see 5 because that is the value of x.

Assigning Empty Variables

If we declare a variable without a value, we can still assign it a value later:

var x;
x = 9;

Learning Goals

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