title: if-not condition fails (jQuery)
body: <p><a href="http://jsbin.com/zexix/1/" rel="noreferrer">http://jsbin.com/zexix/1/</a></p>
  
  <pre><code>$(function() {
  
      if ( !$(".first.last") ) {
        console.log("div with both first and last classes does not exists")
      } else {
        console.log("it exists");
      }
  
  });
  </code></pre>
  
  <p>I want to check if a div with both <code>first</code> and <code>last</code> classes DOES NOT exist, but the check fails.</p>