2.1.1 [DOM Level 3 - Core] Section 1.3.1, String Comparisons in the DOM
The specification states:
The character normalization, i.e. transforming into their fully normalized form as as defined in [XML 1.1], is assumed to happen at serialization time. The DOM Level 3 Load and Save module [DOM Level 3 - LS] provides a serialization mechanism (see the DOMSerializer interface, section 2.3.1) and uses the DOMConfiguration parameters "normalize-characters" and "check-character-normalization" to assure that text is fully normalized [XML 1.1]. Other serialization mechanisms built on top of the DOM Level 3 Core also have to assure that text is fully normalized.
Quirks Mode, IE7 Mode, and IE8 Mode (All Versions)
The DOM Level 3 Load and Save module [DOM Level 3 - LS] is not supported; therefore, this type of character normalization is not supported.