Javascript methods that are easy to mix: typeof and instanceof

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Javascript methods that are easy to mix: typeof and instanceof

September 28, 2011 by Ryan | 1 commentviews: 94 today views: 1

I am often confused by typeof and instanceof in Javascript, so I read it carefully. I hope you will not forget it any more.

Typeof ()

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// Typeof () returns 6 data types: Number, String, Boolean, and Object

// Function and undefined.

VaR A ="String";

Typeof()// Outpout "string"

VaR Fn =Function (){};// Output "function"

Typeof(FN)// Output "function"

Instanceof ()

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// Instanceof () returns a Boolean value. Used to detect objects of one of the six basic types

// Is the instance generated by an object (constructor. Used to trace the prototype chain.

// An example is found online.

VaR A =Function (){};

VaR B =Function (){};

B. Prototype =New A;

VaR C =New B;

VaR D =New A;

Alert (CInstanceof A );// True

Alert (dInstanceof A );// True

Alert (Instanceof Function );// True

Alert ({}Instanceof Function );// False

A. Prototype = {};// Modify the prototype chain

Alert (CInstanceof A );// False

Alert (dInstanceof A );// False

Categories: javascript | tags: instanceof, prototype, typeof | permalink

 

Address: http://www.coolicer.com/2011/09/28/javascript-typeof-and-instanceof.html