We can pass values into a function with arguments. You can use a return statement to send a value back out of a function.

function plusThree(num) {
  return num + 3;
}
var answer = plusThree(5); // 8

plusThree takes an argument for num and returns a value equal to num + 3.

A return statement will also end the execution of it's parent function. Hence, any statements inside a function scope after a return statement will not be executed. In case of multiple return statements in a function, only the first one will get executed.