title: how to check if var is not empty with javascript?
body: <p>Not having much luck with this.  I'm trying to determine if a var is not empty.  </p>
  
  <pre><code>$('#content').mouseup(function() {
  
      var selection = getSelected();
  
      if (typeof(selection) !=='undefined') {
          alert(selection);
      }
  });
  </code></pre>
  
  <p>What this is doing is grabbing any text the user has selected -- but it shows an empty alert even if the user just mouseup's on the div.  </p>