2.2.1 [DOMLevel3Core:2004] Section 1.4, Fundamental Interfaces: Core Module

C0001:

The specification states:

 Method
 hasFeature Test if the DOM implementation implements a specific feature and 
 version, as specified in DOM

Quirks Mode, IE7 Mode, and IE8 Mode (All Versions)

The hasFeature method of the DOMImplementation interface returns false for the Core module and the version strings "1.0", "2.0", and "3.0".

IE9 Mode, IE10 Mode, IE11 Mode, and EdgeHTML Mode (All Versions)

The hasFeature method of the DOMImplementation interface returns false for the Core module and the version string "3.0" because not all DOM L3 Core methods are supported.

C0002:

The specification states:

 createTextNode
 Creates a Text node given the specified string.
 Parameters 
 data of type DOMString
 The data for the node.
  
 Return Value 
 Text
  The new Text object.

Quirks Mode, IE7 Mode, and IE8 Mode (All Versions)

The data parameter of the createTextNode method of the Document interface is optional. A text node is created even when no parameter is provided.

C0003:

The specification states:

 createComment  
 Creates a Comment node given the specified string.

Quirks Mode, IE7 Mode, and IE8 Mode (All Versions)

With the createComment method of the Document interface, the data parameter is treated as optional and creates a Comment node even when no parameter is provided.

C0004:

The specification states:

 getAttribute Retrieves an attribute value by name.
 Parameters name of type DOMStringThe name of the attribute to retrieve.
 Return Value DOMStringThe Attr value as a string, or the empty string if that 
 attribute does not have a specified or default value.
 No Exceptions

Quirks Mode and IE7 Mode (All Versions)

The getAttribute method of the Element interface supports an additional parameter that controls case-sensitivity and object extrapolation (such as for the style object).

C0005:

The specification states:

 Method
 getAttributeNode  Retrieves an attribute node by name.To retrieve an attribute node 
 by qualified name and namespace URI, use the getAttributeNodeNS method.
  
 Parameters 
 name of type DOMString  The name (nodeName) of the attribute to retrieve.
  
 Return Value 
 Attr  The Attr node with the specified name (nodeName) or null if there is no such 
 attribute.
  
 No Exceptions

Quirks Mode and IE7 Mode (All Versions)

The getAttributeNode method of the Element interface returns attribute nodes that have not been specified by the author or have default values other than NULL