function State() {
}

function City() {
}
City.prototype = new State;

function Street() {
}

Street.prototype = new City;

var UniversityAvenue = new Street();

tryIt();

function tryIt() {
  alert(UniversityAvenue.__proto__== Street.prototype);
  alert(UniversityAvenue.__proto__.__proto__== City.prototype);
  alert(UniversityAvenue.__proto__.__proto__.__proto__== State.prototype);
  alert(UniversityAvenue.__proto__.__proto__.__proto__.__proto__== Object.prototype);
  alert(UniversityAvenue.__proto__.__proto__.__proto__.__proto__.__proto__== null);
}

In this example, UniversityAvenue inherits from Street, which inherits from City, which inherits from State. All alert boxes will yield a value of true on Netscape Navigator 4.x and Netscape 6. Try it. Not supported by Internet Explorer.

People who read this tip also read these tips:

• Introducing WML
• Using the Global Response Object
• Detecting a Flash Movie's Loading Progress
• IBuySpy's CustomersDB Component
• Compiling Hello World's Code Behind Version