constructor
Summary
Specifies the function that creates a date.
Syntax
date.constructor
Examples
The following example illustrates the use of the constructor property.
var x = new Date("Hi");
if (x.constructor == Date)
document.write("Object is a date.");
// Output:
// Object is a date.
Remarks
The required date is the name of a date object.
The constructor property is a member of the prototype of every object that has a prototype. The constructor property contains a reference to the function that constructs instances of that particular object.
Attributions
Microsoft Developer Network: Article