HTML5

When examining types to determine if they support the language, user agents must not ignore unknown MIME parameters — types with unknown parameters must be assumed to be unsupported. The charset parameter must be treated as an unknown parameter for the purpose of comparing MIME types here.

The styles might be further limited in scope, e.g. in CSS with the use of @media blocks. This specification does not override such further restrictions or requirements.

If the scoped attribute is present, then the user agent must apply the specified style information only to the style element's parent element (if any), and that element's descendants. Otherwise, the specified styles must, if applied, be applied to the entire document.

The following will eventually be moved to a CSS specification; it is specified here only on an interim basis until an editor can be found to own this.

Within scoped CSS resources, authors may use an @global @-rule. The syntax of this rule is defined as follows.

The following production is added to the grammar:

global
  : GLOBAL_SYM S* ruleset
  ;

The following rules are added to the Flex tokenizer:

B                     b|\\0{0,4}(42|62)(\r\n|[ \t\r\n\f])?
@{G}{L}{O}{B}{A}{L}   {return GLOBAL_SYM;}

Simple selectors in rule sets prefixed by the @global @-rule in scoped CSS resources must be processed in the same way as normal rule sets in non-scoped CSS resources.

Simple selectors in scoped CSS resources that are not prefixed by an @global @-rule must only match the style element's parent element (if any), and that element's descendants.

For scoped CSS resources, the effect of other @-rules must be scoped to either the scoped sheet and its subresources or to the subtree rooted at the style element's parent (if any), even if the @-rule in question would ordinarily apply to all style sheets that affect the Document, or to all nodes in the Document. Any '@page' rules in scoped CSS resources must be ignored.

For example, an '@font-face' rule defined in a scoped style sheet would only define the font for the purposes of elements in the scoped section; the font would not be used for elements outside the subtree. However, rules outside the subtree that refer to font names declared in '@font-face' rules in a scoped section, when those rules are inherited by nodes in the scoped section, would end up referring to the fonts declared in that section.

---

style         = no-c-start *( c-start no-c-end c-end no-c-start )
no-c-start    = <any string that doesn't contain a substring that matches c-start >
c-start       = "<!--"
no-c-end      = <any string that doesn't contain a substring that matches c-end >
c-end         = "-->"

All descendant elements must be processed, according to their semantics, before the style element itself is evaluated. For styling languages that consist of pure text (as opposed to XML), user agents must evaluate style elements by passing the concatenation of the contents of all the Text nodes that are children of the style element (not any other nodes such as comments or elements), in tree order, to the style system. For XML-based styling languages, user agents must pass all the child nodes of the style element to the style system.

All URLs found by the styling language's processor must be resolved, relative to the element (or as defined by the styling language), when the processor is invoked.

Once the attempts to obtain the style sheet's critical subresources, if any, are complete, or, if the style sheet has no critical subresources, once the style sheet has been parsed and processed, the user agent must, if the loads were successful or there were none, queue a task to fire a simple event named load at the style element, or, if one of the style sheet's critical subresources failed to completely load for any reason (e.g. DNS error, HTTP 404 response, a connection being prematurely closed, unsupported Content-Type), queue a task to fire a simple event named error at the style element. Non-network errors in processing the style sheet or its subresources (e.g. CSS parse errors, PNG decoding errors) are not failures for the purposes of this paragraph.

The task source for these tasks is the DOM manipulation task source.

The element must delay the load event of the element's document until all the attempts to obtain the style sheet's critical subresources, if any, are complete.

The media, type and scoped IDL attributes must reflect the respective content attributes of the same name.

<!DOCTYPE html>
<html lang="en-US">
 <head>
  <title>My favorite book</title>
  <style>
   body { color: black; background: white; }
   em { font-style: normal; color: red; }
  </style>
 </head>
 <body>
  <p>My <em>favorite</em> book of all time has <em>got</em> to be
  <cite>A Cat's Life</cite>. It is a book by P. Rahmel that talks
  about the <i lang="la">Felis Catus</i> in modern human society.</p>
 </body>
</html>