jquery的extend方法

Difference between jQuery.extend and jQuery.fn.extend?

一遇到extend或写插件的时候我总是翻几个这样的文章看，终于在stackoverflow上找到了一个很棒的答案。

 

Actually, there is none apart from their base reference. In the jQuery source, you can read:

jQuery.extend = jQuery.fn.extend = function() { … };

So how does it work? The documentation reads:

Merges the contents of two or more objects together into the first object.

It's just a for-in-loop that copies properties, pimped up with a flag to recurse nested objects. And another feature:

If only one argument is supplied to $.extend(), this means the target argument was omitted

// then the following will happen:
 target = this;
jQuery
jQuery.fn