Oelemento HTML<script> é usado para incluir ou referenciar um script executável.

Atributos

Esse elemento inclui osatributos globais.

async

Um atributo booleano indicando que o navegador deve, se possível, executar o script assíncronamente.

Aviso:Esse atributo não deve ser utilizado se o atributosrc estiver ausente (ex. scripts embutidos). Se incluído, nesse caso, ele não terá nenhum efeito.

Scripts inseridos dinamicamente (usandodocument.createElement) são executados assincronamente por padrão, então para torná-lo uma execução síncrona (ex. executar scripts na ordem que eles foram carregados) atribuaasync=false.

VejaBrowser compatibility para notas no suporte do navegador. Veja tambémScripts assíncronos para asm.js.

crossorigin

Elementosscript passam o mínimo de informação parawindow.onerror em scripts que não passem na checagem doCORS. Para permitir logs de erro para sites que usam domínios diferentes para arquivos estáticos, use esse atributo. VejaCORS settings attributes para uma explicação mais detalhada dos argumentos válidos.

defer

Esse atributo Boleano é usado para indicar ao navegador que o script deve ser executado depois que o documento tenha sido parseado, mas antes de disparar o eventoDOMContentLoaded

Scripts com o atributodefer vão impedir que o evento DOMContentLoaded seja disparado até que o script seja carregado e tenha terminado de seravaliado.

Aviso:Esse atributo não deve ser usado se o atibutosrc estiver ausente (ex. scripts inline), nesse caso ele não vai ter efeito.

Para conseguir um efeito similar para scripts inseridos dinamicamente useasync=false. Scripts com o atributodefer vão ser executados na ordem em que aparecem nodocument.

integrity

Contains inline metadata that a user agent can use to verify that a fetched resource has been delivered free of unexpected manipulation. SeeSubresource Integrity.

nomoduleExperimental

This Boolean attribute is set to indicate that the script should not be executed in browsers that supportES6 modules — in effect, this can be used to serve fallback scripts to older browsers that do not support modular JavaScript code.

src

This attribute specifies the URI of an external script; this can be used as an alternative to embedding a script directly within a document. If ascript element has asrc attribute specified, it should not have a script embedded inside its tags.

text

Like thetextContentattribute, this attribute sets the text content of the element. Unlike thetextContent attribute, however, this attribute is evaluated as executable code after the node is inserted into the DOM.

type

Indicates the type of script represented. The value of this attribute will be in one of the following categories:

• Omitted or a JavaScript MIME type: For HTML5-complient browsers this indicates the script is JavaScript. HTML5 spec urges authors to omit the attribute rather than provided a redundant MIME type. In earlier browsers, this identified the scripting language of the embedded or imported (via thesrc attribute) code. JavaScript MIME types arelisted in the specification.
• module: For HTML5-complient browsers the code is treated as a JavaScript module. Processing of the script contents are not affected by thecharset anddefer attributes. For information on usingmodule, seeES6 in Depth: Modules.Experimental
• Any other value or MIME type: Embedded content is treated as a data block which won't be processed by the browser. Thesrc attribute will be ignored.

Note that in Firefox you can use advanced features such as let statements and other features in later JS versions, by usingtype=application/javascript;version=1.8Não padrão. Beware, however, that as this is a non-standard feature, this will most likely break support for other browsers, in particular Chromium-based browsers.

For how to includeexotic programming languages, read aboutRosetta.

Atributos obsoletos

charsetDeprecated

If present, its value must be an ASCII case-insensitive match for "utf-8". Both it's unnecessary to specify thecharset attribute, because documents must use UTF-8, and thescript element inherits its character encoding from the document.

languageDeprecated

Like thetype attribute, this attribute identifies the scripting language in use. Unlike thetype attribute, however, this attribute's possible values were never standardized. Thetype attribute should be used instead.

Notas

Scripts withoutasync ordefer attributes, as well as inline scripts, are fetched and executed immediately, before the browser continues to parse the page.

The script should be served with thetext/javascript MIME type, but browsers are lenient and only block them if the script is served with an image type (image/*), a video type (video/*), an audio (audio/*) type, ortext/csv. If the script is blocked, anerror is sent to the element, if not asuccess event is sent.

Exemplos

<!-- HTML4 and (x)HTML --><script type="text/javascript" src="javascript.js"></script><!-- HTML5 --><script src="javascript.js"></script>

Specifications

Compatibilidade com navegadores

See also

• document.currentScript
• Ryan Grove's <script> and <link> node event compatibility chart