Javascript: Let's Get Started

This line is in a multi-comment block!
Another line!

//This line is in a single comment block!

//Our message variable:
var msg = "Hello";

//Get the users name, put it in the name variable:
var name = prompt("what is your name?");

//If the user entered a name 
if(name != ""){
  document.write(msg + " " + name + " World!");
  alert("you must enter a name!");