Useful undocumented methods and properties of jQuery
<p>I would like to gather all <em>useful</em> undocumented methods and properties of <a href="http://jquery.com/" rel="nofollow"><strong>jQuery</strong></a> (at least for the <a href="http://code.jquery.com/jquery.js" rel="nofollow">current version 1.9.0</a>).</p>

<p>Some of them look quite promising either for solving particular problems, or for accelerating the JavaScript code evaluation.</p>

<p><strong>Important:</strong> Since the listed features here are not documented, it should be used with caution, as new versions of jQuery might not support these features in future releases.</p>
