2. Terminology # T

The following is a list of terms that are used in other sections of this reference.

browsing context

A browsing context is an environment in which UAs present documents to users. A tab or window in a Web browser typically contains a browsing context, as does an iframe, or frame elements in a frameset.

case-insensitive match

For the purposes of this reference, performing a case-insensitive match between two strings means comparing the strings exactly, codepoint for codepoint, except that the characters in the range A-Z and the corresponding characters in the range a-z are considered to also match.

fallback content

Some embedded content elements can have fallback content: content that is to be used when the embedded content cannot be used (for example, when it is of an unsupported format).

flow content

Flow content consists of flow elements intermixed with normal character data.

HTML producers

HTML authors (that is, people) and applications (such as editors and content management systems) that produce HTML content.

HTML consumers

HTML user agents; that is, applications (such as Web browsers) which consume HTML content.

must

The word must is used in this reference to mark document-conformance requirements that are normatively defined in the HTML5: A vocabulary and associated APIs for HTML and XHTML full specification. [HTML5].

This reference does not itself normatively define any requirements.

newline

A newline may be represented as any of the following:

• a U+000D CARRIAGE RETURN (CR) character
• a U+000A LINE FEED (LF) character
• a U+000D CARRIAGE RETURN (CR) followed by a U+000A LINE FEED (LF) character

phrasing content

Phrasing content consists of phrasing elements intermixed with normal character data.

space

A space character is any of the following:

• U+0020 SPACE
• U+0009 CHARACTER TABULATION (tab)
• U+000A LINE FEED (LF)
• U+000C FORM FEED (FF)
• U+000D CARRIAGE RETURN (CR)

transparent

If the content model of a particular element foo is described as transparent, it means:

• when element foo is a child of a parent element bar whose content model is allowed to contain flow elements, then the contents of element foo may also contain flow elements
• when element foo is a child of a parent element baz whose content model restricts its child elements to only being phrasing elements, then any child elements of element foo are also restricted to only being phrasing elements