要在代码中获得结果，您可以:

To get the result in your code, you would do:

function extend(a, b){
    for(var key in b)
        if(b.hasOwnProperty(key))
            a[key] = b[key];
    return a;
}

请记住，您在那里使用扩展的方式将修改默认对象.如果您不想要那样，请使用

Keep in mind that the way you used extend there will modify the default object. If you don't want that, use

$.extend({}, default, config)

模仿 jQuery 功能的更强大的解决方案如下:

A more robust solution that mimics jQuery's functionality would be as follows:

function extend(){
    for(var i=1; i<arguments.length; i++)
        for(var key in arguments[i])
            if(arguments[i].hasOwnProperty(key))
                arguments[0][key] = arguments[i][key];
    return arguments[0];
}