spacer
Yehuda Shiran March 11, 2001
Checking for a Prototype Chain
Tips: March 2001

Yehuda Shiran, Ph.D.
Doc JavaScript

Developer News
Google Going Native With Chrome
Mozilla Fixes Firefox Flaws as 3.5 Release Nears
Microsoft and Novell Still Bosom Buddies

Use the isPrototypeOf() method to find out if object2 had object1 in its prototype chain:

object1.prototype.isPrototypeOf(0bject2);
It returns true if object2 is an object and when object1 appears in the prototype chain of object2. Let's look at an example:

function Person() {
  this.name = "Rob Roberson";
  this.age = 31;
}

function Employee() {
  this.dept = "HR";
  this.manager = "John Johnson";
}

Employee.prototype = new Person();

var Ken = new Employee();

Ken is in the prototype chain of Employee, Person, and Object. Prove it to yourself by clicking on each class. They alert Employee.prototype.isPrototypeOf(Ken), Person.prototype.isPrototypeOf(Ken), and Object.prototype.isPrototypeOf(Ken), respectively.


People who read this tip also read these tips:

Look for similar tips by subject:

internet.commediabistro.comJusttechjobs.comGraphics.com

Search:

WebMediaBrands Corporate Info

Legal Notices, Licensing, Reprints, Permissions, Privacy Policy.
Advertise | Newsletters | Shopping | E-mail Offers | Freelance Jobs

webref The latest from WebReference.com Browse >
XML and PHP Simplified · Creating a ASP.NET Contact Form · Data Filtering with PHP
Sitemap · Experts · Tools · Services · Email a Colleague · Contact FREE Newsletters 
 The latest from internet.com
Intel to Host Live Nehalem Q&A · 12 Tips to Troubleshoot Network File-Sharing · 10 Tips for Selling on Kijiji