26.21 U

• UIEvent: [DOM]

• undefined: [Core]

• unescape: [Core]

• unicodeBidi: CSS2Properties[DOM]

• UNKNOWN_RULE: CSSRule[DOM]

• UNLOAD: Event[Client]

• unshift: Array[Core]

• URIError: [Core]

• URL: [Client], Document[Client], HTMLDocument[DOM]

• useMap: HTMLInputElement[DOM]

• userAgent: Navigator[Client]

• userLanguage: Navigator[Client]

• UTC: Date[Core]