simple_inherit.js

var _hasProp = {}.hasOwnProperty,
_inherit = function (child, parent) {
    for (var key in parent) {
        if (_hasProp.call(parent, key)) child[key] = parent[key];
    }

    if(typeof child === 'string') child = self;

    function ctor() {
        this.constructor = child;
    }

    function self(){parent.apply(this, arguments);};                

    ctor.prototype = parent.prototype;
    child.prototype = new ctor();
    child._super = parent.prototype;
    child.prototype.__super__ = parent;
    return child;
};