JavaScript: The Good Parts

Return

When a function is invoked, it begins execution with the first statement, and ends when it hits the } that closes the function body. That causes the function to return control to the part of the program that invoked the function.

The return statement can be used to cause the function to return early. When return is executed, the function returns immediately without executing the remaining statements.

A function always returns a value. If the return value is not specified, then undefined is returned.

If the function was invoked with the new prefix and the return value is not an object, then this (the new object) is returned instead.