hasOwnProperty Method (Object) (JavaScript)

object

Required. Instance of an object.

proName

Required. String value of a property name.

The hasOwnProperty method returns true if object has a property of the specified name, false if it does not. This method does not check the properties in the object's prototype chain; the property must be a member of the object itself.

In the following example, all String objects share a common split method. The following code will display false and true.

var s = new String("Sample");
document.write(s.hasOwnProperty("split"));
document.write("<br/>");
document.write(String.prototype.hasOwnProperty("split"));

// Output:
// false
// true

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. Also supported in Windows Store apps. See Version Information.

Reference