Template:Function Constructor

// Colorized is a constructor.
function Colorized(name, favoriteColor) {
  this.name = name;
  this.favoriteColor = favoriteColor;
}

// c is an instance of Colorized.
var c = new Colorized("Mary", "red");
alert(c.toString());

A toString method is available on every native object. This is because toString is defined on Object.prototype and Object.prototype is at the base the prototype chain.