isPrototypeOf()  Object  instance method JS Home  <<  JS Reference  <<  Object  <<  isPrototypeOf()

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Description

Returns a boolean indicating whether the object exists in another objects hierarchy.

Syntax

Parameters

Examples

The code below checks objects against a prototype chain.

// Create Prototypes.
function AFunc(aProp) {  
  this.aProp=aProp;  
}  

function BFunc(bProp) {  
  this.bProp=bProp;  
}

BFunc.prototype = new AFunc();

function CFunc(cProp) {  
  this.cProp=cProp;  
}
 
CFunc.prototype = new AFunc(); 

// Create an object and check against prototype chains.
var cObj = new CFunc();

if (AFunc.prototype.isPrototypeOf(cObj)) {
  alert('AFunc is prototype of CFunc')
} else {
  alert('AFunc is NOT a prototype of CFunc')
}

if (BFunc.prototype.isPrototypeOf(cObj)) {
  alert('BFunc is prototype of CFunc')
} else {
  alert('BFunc is NOT a prototype of CFunc')
} 

Related Tutorials

JavaScript Basic Tutorials - Lesson 7 - Objects

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