title: javascript isNaN() function not working?
body: <p>I have a function to test if a prompt input is a number, like so:</p>
  
  <pre><code>function myFunction() 
  {
      var person = prompt("Please enter your name", "");
  
      if (person != null) 
      {
          if(isNaN(person))
          {
              document.write("hello " + person + "&lt;br&gt;&lt;br&gt;");
          }
          else
              document.write("You gave me a number");
  
      }
      else
      {
          document.write("You didn't answer.&lt;br&gt;&lt;br&gt;");
      }
  }
  </code></pre>
  
  <p>but every time I enter a number it keeps outputting hello + the number. I've been googling this function for quite some time and it doesn't make sense to me, it seems like it should work. Why is person returning true?</p>