But since the DTD states that paragraph elements cannot be nested, an HTML document fragment Para 1 Para 2 Para 3 is thus inferred to be equivalent to Para 1 Para 2 Para 3. As a simple example, the tag indicating the start of a paragraph element should be complemented by a tag indicating its end. It is part of general SGML behavior that, where only one valid structure is possible (per the DTD), its explicit statement in any given document is not generally required. it defines the set of element types) and also the valid combinations in which they may appear in a document. The DTD specifies which element types are possible (i.e. Optional tagsĪs HTML (before HTML5) is based on SGML, its parsing also depends on the Document Type Definition (DTD), specifically an HTML DTD (e.g. The contents of the element must be placed between just after the start tag (which might be implied, in certain cases) and just before the end tag (which again, might be implied, in certain cases). (.) The start and end tags of certain normal elements can be omitted, (.) Tags are used to delimit the start and end of elements in the markup. Similarly the W3C Recommendation HTML 5.1 2nd Edition explicitly says: For instance, the HEAD element is always present, even though both start and end HEAD tags may be missing in the markup. Remember that the element is one thing, and the tag (be it start or end tag) is another. Some people refer to elements as tags (e.g., 'the P tag'). The distinction is explicitly emphasised in HTML 4.01 Specification:Įlements are not tags.

This is the case for many, but not all, elements within an HTML document. tags Īs is generally understood, the position of an element is indicated as spanning from a start tag and is terminated by an end tag. Elements can also have content, including other elements and text.Ĭoncepts HTML element content categories Elements vs.

Each element can have HTML attributes specified. The current de facto standard is governed by the industry group WHATWG and is known as the HTML Living Standard.Īn HTML document is composed of a tree of simple HTML nodes, such as text nodes, and HTML elements, which add semantics and formatting to parts of document (e.g., make text bold, organize it into paragraphs, lists and tables, or embed hyperlinks and images). The first used version of HTML was written by Tim Berners-Lee in 1993 and there have since been many versions of HTML. An HTML element is a type of HTML (HyperText Markup Language) document component, one of several types of HTML nodes (there are also text nodes, comment nodes and others).

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