reserved words

Summary

Reserved words are words that you cannot use as identifiers in JavaScript.

Syntax

Remarks

JavaScript has a number of reserved words that you cannot use as identifiers. Reserved words have a specific meaning to the JavaScript language, as they are part of the language syntax. Using a reserved word causes a compilation error when loading your script.

Notes

Future reserved words

JavaScript also has a list of future reserved words. These words are not currently part of the JavaScript language, although they are reserved for future use. For more information about future reserved keywords in JavaScript, see JavaScript Future Reserved Words.

Intrinsic objects or functions

When choosing identifiers it is also important to avoid any words that are already the names of intrinsic JavaScript objects or functions, such as String or parseInt.

Reserved Keywords

break
case
catch
continue
debugger
default
delete
do
else
finally
for
function
if
in
instanceof
new
return
switch
this
throw
try
typeof
var
void
while
with
yield

Attributions

Microsoft Developer Network: Article