title: Best way to reference root html element with jQuery?
body: <p>Which is the best way (performance-wise) to get the root document node (the <code>&lt;html&gt;</code> element) in jQuery? I can think of several methods that may or may not work:</p>
  
  <p><code>$("html")</code></p>
  
  <p><code>$(document.documentElement)</code></p>
  
  <p><code>$(document)</code> (?)</p>
  
  <p><code>$.root</code> (?)</p>
  
  <p><code>$.document</code> (?)</p>