$.extend

console.log(jQuery.extend(this,{'a':'b'},{'c':'d'}));
console.log(this.a)
var tt = jQuery.extend({},{'a':'b'},{'c':'d'});
console.log(tt);

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http://www.cnblogs.com/RascallySnake/archive/2010/05/07/1729563.html

这个例子是非常好的。