hasOwnProperty

Summary

Determines whether an object has a property with the specified name.

Syntax

hasOwnProperty( proName )

proName

Required. String value of a property name.

Examples

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

Remarks

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.

See also

Specification

15.2.4.5 Object.prototype.hasOwnProperty (V) ECMAScript® Language Specification Standard ECMA-262 5.1 Edition / June 2011

Attributions

• Microsoft Developer Network: Article