This isn’t a compleate list of reserved words, but it’s a good start. For a complete list look in the ECMAScript standards documents. Also useful in fighting insomnia. Reserved words cannot be used to name variables, functions, methods, or as object identifiers.

Cannot Use

abstract else instanceof super
boolean enum int switch
break export interface synchronized
byte extends let this
case false long throw
catch final native throws
char finally new transient
class float null true
const for package try
continue function private typeof
debugger goto protected var
default if public void
delete implements return volatile
do import short while
double in static with

Ought not use

alert frames outerHeight
all frameRate outerWidth
anchor function packages
anchors getClass pageXOffset
area hasOwnProperty pageYOffset
Array hidden parent
assign history parseFloat
blur image parseInt
button images password
checkbox Infinity pkcs11
clearInterval isFinite plugin
clearTimeout isNaN prompt
clientInformation isPrototypeOf propertyIsEnum
close java prototype
closed JavaArray radio
confirm JavaClass reset
constructor JavaObject screenX
crypto JavaPackage screenY
Date innerHeight scroll
decodeURI innerWidth secure
decodeURICompo nent layer select
defaultStatus layers self
document length setInterval
element link setTimeout
elements location status
embed Math String
embeds mimeTypes submit
encodeURI name taint
encodeURIComponent NaN text
escape navigate textarea
eval navigator top
event Number toString
fileUpload Object undefined
focus offscreenBuffering unescape
form open untaint
forms opener valueOf
frame option window