title: if else in coffee script
body: <p>Folks,</p>
  
  <p>I have two text boxes in my html. I wanted to compare their values using coffee script. Although I have googled about it, and I am kind of sure that I am doing what is expected to do but still I see a strange behavior.</p>
  
  <p>Thing is :</p>
  
  <p>Lets say, I have two text boxes with id as "title" and "author". Along with that, I have a button which onclick triggers the coffee script function.</p>
  
  <p>My coffee script function looks as:</p>
  
  <pre><code>check_fields = -&gt;
    elem_book_title  = $("#title").val()
    elem_book_author = $("#author").val()
    alert(elem_book_title)
    alert(elem_book_author)
    if not elem_book_title? 
      alert("title is null")
    else if not elem_book_author?
      alert("author is null")
    else
      alert("both are ok")
  </code></pre>
  
  <p>Situation is, If I enter something only in my "title" textbox, it should alert me that "author is null". Right? But surprisingly, it alerts me that  "both are ok".. Expected? Or I missed something?</p>