prototype-property-object-javascript.md

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prototype Property (Object) (JavaScript) | Microsoft Docs		01/18/2017	windows-client-threshold			devlang-javascript		language-reference	Prototype	JavaScript TypeScript DHTML	inheritance, objects Prototype property	9fc434a1-5995-4fcb-a4e8-00e7f615aaa2	11	mikejo5000	mikejo	ghogen

prototype Property (Object) (JavaScript)

Returns a reference to the prototype for a class of objects.

Syntax

  
objectName.prototype  

Remarks

The objectName argument is the name of an object.

Use the prototype property to provide a base set of functionality to a class of objects. New instances of an object "inherit" the behavior of the prototype assigned to that object.

For example, to add a method to the Array object that returns the value of the largest element of the array, declare the function, add it to Array.prototype, and then use it.

function array_max( ){  
    var i, max = this[0];  
    for (i = 1; i < this.length; i++)  
    {  
    if (max < this[i])  
    max = this[i];  
    }  
    return max;  
}  
Array.prototype.max = array_max;  
var myArray = new Array(7, 1, 3, 11, 25, 9  
);  
document.write(myArray.max());  
  
// Output:  
// 25  
  

All intrinsic [!INCLUDEjavascript] objects have a prototype property that is read-only. Properties and methods may be added to the prototype, but the object may not be assigned a different prototype. However, user-defined objects may be assigned a new prototype.

The method and property lists for each intrinsic object in this language reference indicate which ones are part of the object's prototype, and which are not.

Requirements

[!INCLUDEjsv2]

See Also

constructor Property (Object)