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undefined

The undefined property of the Global object represents the return value "undefined". This value is returned to the script any time a variable value or object property is undefined in the script.

Getting "undefined" from an undefined variable value: var x; alert( x ); Getting "undefined" from an undefined object property: var obj = { a:20, b:50, c:40 }; alert( obj.d );

JavaScript

Properties

bodycalleeclosedcookiedocumentdropEffecteffectAllowedfilesframeElementframeshistoryInfinityinnerHeightinnerHTMLinnerWidthlengthlocationlocationbarnameNaNnavigatornullopenerouterHeightparentprototypescreenstatetextContentundefined