Editing HTML (section)

=== HTTP ===
{{Main|Hypertext Transfer Protocol}}
The [[World Wide Web]] is composed primarily of HTML documents transmitted from web servers to web browsers using the [[Hypertext Transfer Protocol]] (HTTP). However, HTTP is used to serve images, sound, and other content, in addition to HTML. To allow the web browser to know how to handle each document it receives, other information is transmitted along with the document. This [[meta data]] usually includes the [[MIME type]] (e.g., <kbd>text/html</kbd> or <kbd>application/xhtml+xml</kbd>) and the character encoding (see [[Character encodings in HTML]]).

In modern browsers, the MIME type that is sent with the HTML document may affect how the document is initially interpreted. A document sent with the XHTML MIME type is expected to be [[Well-formed document|well-formed]] XML; syntax errors may cause the browser to fail to render it. The same document sent with the HTML MIME type might be displayed successfully since some browsers are more lenient with HTML.

The W3C recommendations state that XHTML 1.0 documents that follow guidelines set forth in the recommendation's Appendix C may be labeled with either MIME Type.<ref>{{cite web|url=https://www.w3.org/TR/xhtml1/#media|title=XHTML 1.0 The Extensible HyperText Markup Language (Second Edition)|publisher=World Wide Web Consortium|orig-date=2000|year=2002|access-date=December 7, 2008|quote=XHTML Documents which follow the guidelines set forth in Appendix C, "HTML Compatibility Guidelines" may be labeled with the Internet Media Type "text/html" [RFC2854], as they are compatible with most HTML browsers. Those documents, and any other document conforming to this specification, may also be labeled with the Internet Media Type "application/xhtml+xml" as defined in [RFC3236].}}</ref> XHTML 1.1 also states that XHTML 1.1 documents should{{Ref RFC|2119|quote=3. SHOULD This word, or the adjective "RECOMMENDED", mean that there may exist valid reasons in particular circumstances to ignore a particular item, but the full implications must be understood and carefully weighed before choosing a different course. }} be labeled with either MIME type.<ref>{{cite web|url=https://www.w3.org/TR/xhtml11/conformance.html#strict|title=XHTML 1.1 – Module-based XHTML&nbsp;— Second Edition|publisher=World Wide Web Consortium|year=2007|access-date=December 7, 2008|quote=XHTML 1.1 documents SHOULD be labeled with the Internet Media Type text/html as defined in [RFC2854] or application/xhtml+xml as defined in [RFC3236].}}</ref>