--- title: XHTML slug: Glossary/XHTML tags: - CodingScripting - Glossário - XHTML translation_of: Glossary/XHTML original_slug: XHTML ---

HTML pode viajar através da rede para um navegador quer em sintaxe de HTML ou uma sintaxe chamada de XML.

HTML5 e HTML/XHTML

O padrão de HTML5 define ambas as sintaxes. O tipo MIME (enviado no cabeçalho Content-Type de HTTP) indica a escolha da sintaxe: para XHTML o tipo MIME irá ser application/xhtml+xml, de outro modo  text/html.

Este exemplo mostra um documento HTML e um documento XHTML incluindo os cabeçalhos de HTTP apropriados:

Documento HTML

HTTP/1.1 200 OK
Content-Type: text/html

<!DOCTYPE html>
<html lang=en>
  <head>
    <meta charset=utf-8>
    <title>HTML</title>
  </head>
  <body>
    <p>I am a HTML document</p>
  </body>
</html>

Documento XHTML

HTTP/1.1 200 OK
Content-Type: application/xhtml+xml

<html xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <title>XHTML</title>
  </head>
  <body>
    <p>I am a XHTML document</p>
  </body>
</html>

Tipo MIME versus DOCTYPE

Before HTML5, the two separate specifications defined the two syntaxes (HTML 4.01 and XHTML 1.0). According to the XHTML1 standard, you could use XHTML by declaring a special DOCTYPE. However, no browsers have ever implemented this, and the HTML5 standard has reversed the decision. If your page is sent as text/html, you are not using XHTML.

Instead, the proper MIME type must be present in the Content-Type HTTP header. If you only put the MIME type into an HTML meta tag like <meta http-equiv=…>, it will be ignored and treated like text/html.

If you serve your pages as text/html and believe that you are writing XHTML, you may face several problems, as described in these articles:

Suporte

Most browsers currently support XHTML, including Firefox, Chrome, Safari, Opera, and Internet Explorer (since IE 9). (Internet Explorer 8 and older browsers instead show a download dialog box for unknown file types when they see an XHTML document with the correct XHTML MIME type.)

Also be aware that many popular {{Glossary("JavaScript")}} libraries and developer tools have limited or no support for XHTML.

Diferençãs do HTML

See Properly Using CSS and JavaScript in XHTML Documents for a partial list of differences between HTML and XHTML.

Ferramentas

Consulte também

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