what's the meaning of the way of writing in jquery?
<pre><code>$.each(obj,function(key,value) {})
</code></pre>

<p>I am a newbie of jquery, i know there are two ways to write the structure like this:</p>

<pre><code>$('document').ready(function(){}); or     $(function(){});
</code></pre>

<p>why <code>$.each()</code> put <code>.</code> behind <code>$</code> rather than <code>$(each())</code></p>

<p>`</p>
