var first_name = "Dusty";
var keyword declares the variable, while the assignment operator (
=) assigns it the string value
Dusty. The expression that follows the assignment operator is optional. It is often referred to as the initializer expression. When you assign your variable a value it is called "initializing".
It's possible to declare multiple variables at once like this:
var first_name, middle_name, last_name;
It's also possible to declare and initialize these variables all at once like this:
var first_name = "Dusty", middle_name = "Armadillo", last_name = "Arlia";
Remember that the initializer expressions are optional and not required.
undefined to the value assigned to it.
Accidentally declaring the same variable multiple times has no effect and is harmless.