constructor Property (Object) (JavaScript)

Specifies the function that creates an object.




The required object is the name of an object or function.

The constructor property is a member of the prototype of every object that has a prototype. This includes all intrinsic JavaScript objects except the Global and Math objects. The constructor property contains a reference to the function that constructs instances of that particular object.


The following example illustrates the use of the constructor property.

// A constructor function.  
function MyObj() {  
    this.number = 1;  

var x = new String("Hi");  

if (x.constructor == String)  
    document.write("Object is a String.");  
document.write ("<br />");  

var y = new MyObj;  
if (y.constructor == MyObj)  
    document.write("Object constructor is MyObj.");  

// Output:  
// Object is a String.  
// Object constructor is MyObj.  


Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards, Internet Explorer 11 standards. Also supported Store apps (Windows 8 and Windows Phone 8.1). See Version Information.

See Also

prototype Property (Object)