18841 2012-09-11 23:40:13 +0000 [Custom]: "extends" is an ECMAScript reserved word; don’t use it as an attribute name 2012-10-24 20:10:37 +0000 1 1 1 Unclassified WebAppsWG HISTORICAL - Component Model unspecified PC All RESOLVED INVALID P2 normal --- 17103 1 dominicc dglazkov erik.arvidsson public-webapps-bugzilla oldest_to_newest 73647 0 dominicc 2012-09-11 23:40:13 +0000 "extends" is a reserved word in JavaScript and illegal in strict mode. Thus it is inconvenient to access the HTMLElementElement.extends attribute from JavaScript. Consider using a different name. 77063 1 dglazkov 2012-10-24 19:54:30 +0000 Isn't it only illegal as a variable? I think it still totally works as an property name: http://jsfiddle.net/pQa2w/ 77065 2 erik.arvidsson 2012-10-24 20:10:37 +0000 Property names are using the IdentifierName production which allows reserved keywords: Identifier :: IdentifierName but not ReservedWord IdentifierName :: IdentifierStart IdentifierName IdentifierPart Other productions, like variable bindings and function name bindings uses the Identifier production which may not include reserved keywords.