HyperText Transport Protocol Kornel Lesiński London Web Standards 2011 

“HTM L5” AKA N.E.W .T. HTML5 Video CSS3 Server-sent events XHTML5 Web Sockets Live Streaming NoSQL DB the actual XMLHttpRequest Web APIs 

http:// 

Server Client Proxy (sometimes) 

HTTP/1.1'200'OK Date:'Tue,'18'Jan'2011'20:00:00'GMT' Server:'Apache' ContentAType:'text/html;'charset=utfA8 LastAModified:'Wed,'08'Sep'2010'06:34:43'GMT' ContentALength:'5447' ContentALanguage:'enAGBAxAHixie' Connection:'close' ' ''Web'Hypertext'Application'Technology' Working'Group '' '' ' ' '''Welcome'to'the'WHATWG'community ''Maintaining'and'evolving' HTML'since'2004

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HTTP/1.1'200'OK Date:'Tue,'18'Jan'2011'20:00:00'GMT' Server:'Apache' ContentAType:'text/html;'charset=utfA8 LastAModified:'Wed,'08'Sep'2010'06:34:43'GMT' ContentALength:'5447' ContentALanguage:'enAGBAxAHixie' Connection:'close' ' ''Web'Hypertext'Application'Technology' Working'Group '' '' ' ' '''Welcome'to'the'WHATWG'community ''Maintaining'and'evolving' HTML'since'2004

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Want'to'get'involved' and'help'out?'See'a'list'of'things'for' which'we'need'volunteers'and'jump'in!

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HTTP/1.1'200'OK Date:'Tue,'18'Jan'2011'20:00:00'GMT' Server:'Apache' ContentAType:'text/html;'charset=utfA8 LastAModified:'Wed,'08'Sep'2010'06:34:43'GMT' ContentALength:'5447' ContentALanguage:'enAGBAxAHixie' Connection:'close' ' '' ''Web'Hypertext'Application'Technology' Working'Group '' '' ' ' '''Welcome'to'the'WHATWG'community ''Maintaining'and'evolving' HTML'since'2004

''

Want'to'get'involved' and'help'out?'See'a'list'of'things'for' which'we'need'volunteers'and'jump'in!

''FAQ'Get' 

HTTP/1.1'200'OK Date:'Tue,'18'Jan'2011'20:00:00'GMT' Server:'Apache' ContentAType:'text/html;'charset=utfA8 LastAModified:'Wed,'08'Sep'2010'06:34:43'GMT' ContentALength:'5447' ContentALanguage:'enAGBAxAHixie' Connection:'close' ' '' ''Web'Hypertext'Application'Technology' Working'Group '' '' ' ' '''Welcome'to'the'WHATWG'community ''Maintaining'and'evolving' HTML'since'2004

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Want'to'get'involved' and'help'out?'See'a'list'of'things'for' which'we'need'volunteers'and'jump'in!

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not even close to equivalent 

Force download of a file Open Save Cancel 

Content&Disposition:,attachment 

Cache&Control:,public,,private, ,must&revalidate,,no&validate,,pre& cache=0,,post&check=0,,max&age=&1 Pragma:,cache Transfer&Description:,download Content&Disposition:,attachment; ,filename*=UTF&8''name Content&Type:,downloadpls/kthxbye X&Pragma:,no&cache Expires:,0 Content&Transfer&Encoding:,binary Content&Disposition:,attachment 

/riaa%20bait/Mot%C3%B6rhead.mp3 

Content&Type: image/png flickr.com/photos/ veggietothemax/ 201197734 

.htaccess AddType,video/webm,.webm AddType,video/ogg,.ogv /etc/mime.types 

HTML = text/html XHTML = application/xhtml+xml 

http://lists.w3.org/Archives/Public/www-html/2000Sep/0024.html The HTML WG has discussed this issue: the intention was to allow old (HTML-only) browsers to accept XHTML 1.0 documents by following the guidelines, and serving them as text/html. Therefore, documents served as text/html should be treated as HTML and not as XHTML. There should be no sniffing of text/html documents to see if they are really XHTML. Note that there are some semantic differences between HTML documents and XHTML documents: there are specific CSS rules that only apply to HTML (and not XHTML), and the DOM has different effects (for instance, the element names are returned in uppercase for HTML, and lower case for XHTML). Best wishes, Steven Pemberton Chair, W3C HTML WG ” “ 

Firefox Strict MIME type Safari Strict MIME type Opera Strict MIME type Internet Explorer Strict MIME type W3C Validator Sniffs DOCTYPE http://www.w3.org/Bugs/Public/show_bug.cgi?id=1500 

No content

No content

No content

No content

I reckoned HTML5 was at least partly Hixie’s revenge against XHTML served as text/html. 

RFC 2616 

2011 * not to scale HTTP 

Connection:,close 

http://pornel.net/1 http://pornel.net/2 HTTP/1.0'200'OK ContentAType:'text/html What'color'is'it? HTTP/1.0'200'OK ContentAType:'application/xhtml+xml What'color'is'it? What'color'is'it? What'color'is'it?