Function.bind.js

Function.prototype.bind = function(bind){
    var self = this, args = Array.slice(arguments), args = (args.length > 1) ? args.slice(1) : null;
    return function bound(){
        if (this instanceof bound){
            var F = function(){};
            F.prototype = new self;
            bind = new F;
        }

        args = args.concat(Array.slice(arguments));
        var result = !args ? self.call(bind) : self.apply(bind, args);
        return F ? bind : result;
    };
};