title: What is the difference in Javascript between 'undefined' and 'not defined'?
body: <p>If you attempt to use a variable that does not exist and has not been declared, javascript will throw an error. <code>var name is not defined</code>, and the script will stop then and there.</p>
  
  <p>But if you check it using <code>typeof noname</code> then it will return <code>"undefined"</code>. I always thought that you had to declare a var for it to have a type. Either by using: var a; so it has the type of undefined or by giving it a value like: <code>var b =5;</code> so it has the type of its value.</p>
  
  <p>Also what is the difference between <code>var a;</code> and <code>var b = undefined;</code>?</p>