[Rise]

ivanWantsToKnow,

function Animal () {
    this.run = function () {
        if (this.constructor === Beaver) {
            console.log('beaver running');
        } else if (this.constructor === Deer) {
            console.log('deer running');
        }
    };
}
 
function Beaver () {
}
Beaver.prototype = new Animal();
Beaver.prototype.constructor = Beaver;
 
function Deer () {
}
Deer.prototype = new Animal();
Deer.prototype.constructor = Deer;
 
var deer = new Beaver();
deer.run();