---
title: Javascript Reserved Words
description: "> In JavaScript you cannot use these reserved words as variables, labels, or function names: | abstract | arguments | await* | boolean | | --- | --- | --- | --- | | break | byte | case |…"
url: "https://apprentice.mn/docs/javascript-reserved-words/"
updated: "2021-05-18"
category: Javascript
---

# Javascript Reserved Words

> In JavaScript you cannot use these reserved words as variables, labels, or function names:

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

> Words marked with* are new in ECMAScript 5 and 6.
>
>   You can read more about the different JavaScript versions in the chapter JS Versions.
>
> ---
>
>
>
> ## Removed Reserved Words
>
>
>
> The following reserved words have been removed from the ECMAScript 5/6 standard:
>
>
>
> | abstract | boolean | byte | char |
> | --- | --- | --- | --- |
> | double | final | float | goto |
> | int | long | native | short |
> | synchronized | throws | transient | volatile |
>
>
>
> Do not use these words as variables. ECMAScript 5/6 does not have full support in all browsers.
>
>
>
> ---
>
>
>
> ---
>
>
>
> ## JavaScript Objects, Properties, and Methods
>
>
>
> You should also avoid using the name of JavaScript built-in objects, properties, and methods:
>
>
>
> | Array | Date | eval | function |
> | --- | --- | --- | --- |
> | hasOwnProperty | Infinity | isFinite | isNaN |
> | isPrototypeOf | length | Math | NaN |
> | name | Number | Object | prototype |
> | String | toString | undefined | valueOf |
>
>
>
> ---
>
>
>
> ## Java Reserved Words
>
>
>
> JavaScript is often used together with Java. You should avoid using some Java objects and properties as JavaScript identifiers:
>
>
>
> | getClass | java | JavaArray | javaClass |
> | --- | --- | --- | --- |
> | JavaObject | JavaPackage |  |  |
>
>
>
> ---
>
>
>
> ## Other Reserved Words
>
>
>
> JavaScript can be used as the programming language in many applications.
>
>
>
> You should also avoid using the name of HTML and Window objects and properties:
>
>
>
> | alert | all | anchor | anchors |
> | --- | --- | --- | --- |
> | area | assign | blur | button |
> | checkbox | clearInterval | clearTimeout | clientInformation |
> | close | closed | confirm | constructor |
> | crypto | decodeURI | decodeURIComponent | defaultStatus |
> | document | element | elements | embed |
> | embeds | encodeURI | encodeURIComponent | escape |
> | event | fileUpload | focus | form |
> | forms | frame | innerHeight | innerWidth |
> | layer | layers | link | location |
> | mimeTypes | navigate | navigator | frames |
> | frameRate | hidden | history | image |
> | images | offscreenBuffering | open | opener |
> | option | outerHeight | outerWidth | packages |
> | pageXOffset | pageYOffset | parent | parseFloat |
> | parseInt | password | pkcs11 | plugin |
> | prompt | propertyIsEnum | radio | reset |
> | screenX | screenY | scroll | secure |
> | select | self | setInterval | setTimeout |
> | status | submit | taint | text |
> | textarea | top | unescape | untaint |
> | window |  |  |  |
>
>
>
> ---
>
>
>
> ## HTML Event Handlers
>
>
>
> In addition you should avoid using the name of all HTML event handlers.
>
>
>
> Examples:
>
>
>
> | onblur | onclick | onerror | onfocus |
> | --- | --- | --- | --- |
> | onkeydown | onkeypress | onkeyup | onmouseover |
> | onload | onmouseup | onmousedown | onsubmit |

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