JavaScript: The Definitive Guide, Fourth Edition

Name

DOMImplementation.hasFeature( ) — determine whether the implementation supports a feature

Availability

DOM Level 1 Core

Synopsis

boolean hasFeature(String feature, 
                   String version);

Arguments

feature

The name of the feature for which support is being tested. The set of valid feature names for the DOM Level 2 standard is listed in the upcoming table. Feature names are case-insensitive.

version

The feature version number for which support is being tested, or null or the empty string "" if support for any version of the feature is sufficient. In the Level 2 DOM specification, supported version numbers are 1.0 and 2.0.

Returns

true if the implementation completely supports the specified version of the specified feature, or false otherwise. If no version number is specified, the method returns true if the implementation completely supports any version of the specified feature.

Description

The W3C DOM standard is modular, and implementations are not required to implement all modules or features of the standard. This method is used to test whether a DOM implementation supports a named module of the DOM specification. The availability information for each entry in this DOM reference includes the name of the module. Note that although Internet Explorer 5 and 5.5 include partial support for the DOM Level 1 specification, this important method is not supported before IE 6.

The complete set of module names that may be used as the feature argument are shown in the following table.

Feature ...