(registered 2012-09-19, updated 2014-05-27) Name : Robin Berjon Email : robin&w3.org MIME media type name : Text MIME subtype name : Standards Tree - html Required parameters : No required parameters Optional parameters : charset The charset parameter may be provided to definitively specify the document's character encoding, overriding any character encoding declarations in the document. The parameter's value must be one of the labels of the character encoding used to serialize the file. Encoding considerations : 8bit Security considerations : Entire novels have been written about the security considerations that apply to HTML documents. Many are listed in the published specification, to which the reader is referred for more details. Some general concerns bear mentioning here, however: HTML is scripted language, and has a large number of APIs (some of which are described in the published specification). Script can expose the user to potential risks of information leakage, credential leakage, cross-site scripting attacks, cross-site request forgeries, and a host of other problems. While the designs in this specification are intended to be safe if implemented correctly, a full implementation is a massive undertaking and, as with any software, user agents are likely to have security bugs. Even without scripting, there are specific features in HTML which, for historical reasons, are required for broad compatibility with legacy content but that expose the user to unfortunate security problems. In particular, the img element can be used in conjunction with some other features as a way to effect a port scan from the user's location on the Internet. This can expose local network topologies that the attacker would otherwise not be able to determine. HTML relies on a compartmentalization scheme sometimes known as the same-origin policy. An origin in most cases consists of all the pages served from the same host, on the same port, using the same protocol. It is critical, therefore, to ensure that any untrusted content that forms part of a site be hosted on a different origin than any sensitive content on that site. Untrusted content can easily spoof any other page on the same origin, read data from that origin, cause scripts in that origin to execute, submit forms to and from that origin even if they are protected from cross-site request forgery attacks by unique tokens, and make use of any third-party resources exposed to or rights granted to that origin. Interoperability considerations : Rules for processing both conforming and non-conforming content are defined in the published specification. Published specification : http://www.w3.org/TR/html Applications which use this media : Web browsers, tools for processing Web content, HTML authoring tools, search engines, validators. Fragment identifier considerations : Fragment identifiers used with text/html resources either refer to the indicated part of the document or provide state information for in-page scripts. Detailed processing for fragment identifiers is defined in the "Navigating to a fragment identifier" section (http://www.w3.org/TR/html/browsers.html#scroll-to-fragid). Restrictions on usage : No restrictions apply. Provisional registration? (standards tree only) : No. Additional information : 1. Deprecated alias names for this type : N/A 2. Magic number(s) : No sequence of bytes can uniquely identify an HTML document. 3. File extension(s) : "html" and "htm" are commonly used. 4. Macintosh file type code : TEXT 5. Object Identifiers: N/A Person to contact for further information : 1. Name : Robin Berjon 2. Email : robin&w3.org Intended usage : Common N/A Author/Change controller : Author: Ian Hickson Change controller: W3C