Editing HTML element (section)

===SGML vs. XML===
SGML is complex, which has limited its widespread understanding and adoption. [[XML]] was developed as a simpler alternative. Although both can use the DTD to specify the supported elements and their permitted combinations as document structure, XML parsing is simpler. The relation from tags to elements is always that of parsing the actual tags included in the document, without the implied closures that are part of SGML.{{refn|group=note|A macro-like feature of DTDs may still be used within XML.}}

HTML as used on the current web is likely to be either treated as XML, by being [[XHTML]], or as [[HTML5]]; in either case the parsing of document tags into [[Document Object Model]] (DOM) elements is simplified compared to legacy HTML systems. Once the DOM of elements is obtained, behavior at higher levels of interface (example: screen rendering) is identical or nearly so.{{refn|group=note|One minor difference is that XML, even after the DOM interface, is case-sensitive.<ref>{{Cite web
  |at=§1.3. XHTML and the HTML DOM
  |work=Document Object Model (DOM) Level 2 HTML Specification
  |date=9 January 2003
  |title=§1. Document Object Model HTML
  |url=http://www.w3.org/TR/2003/REC-DOM-Level-2-HTML-20030109/html.html#ID-5353782642
  |publisher=[[W3C]]
}}</ref>}}