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	Description
Core	Node, Element, Document, Text, and the other fundamental interfaces required by all DOM implementations are implemented. All conforming implementations must support this module.
HTML	HTMLElement, HTMLDocument, and the other HTML-specific interfaces are implemented.
XML	Entity, EntityReference, ProcessingInstruction, Notation, and the other node types that are useful only with XML documents are implemented.
StyleSheets	Simple interfaces describing generic style sheets are implemented.
CSS	Interfaces that are specific to CSS style sheets are implemented.
CSS2	The CSS2Properties interface is implemented.
Events	The basic event-handling interfaces are implemented.
UIEvents	The interfaces for user-interface events are implemented.
MouseEvents	The interfaces for mouse events are implemented.
HTMLEvents	The interfaces for HTML events are implemented.
MutationEvents	The interfaces for document mutation events are implemented.
Range	The interfaces for manipulating ranges of a document are implemented.
Traversal	The interfaces for advanced document traversal are implemented.
Views	The interfaces for document views are implemented.

Example

You might use this method in code like the following:

// Check whether the browser supports the DOM Level 2 Traversal API
if (document.implementation &&
    document.implementation.hasFeature &&
    document.implementation.hasFeature("Traversal", "2.0")) {
  // If so, use it here...
}
else {
  // If not, traverse the document some other way
} 

See Also

Node.isSupported( )