Upgrade to Pro — share decks privately, control downloads, hide ads and more …

∞ things I didn’t know about HTML, CSS, and Jav...

Avatar for Mathias Bynens Mathias Bynens
March 01, 2014
Programming
11
3.9k

∞ things I didn’t know about HTML, CSS, and JavaScript @ Kod.io 2014

Slides for my talk on random web development fun facts at Kod.io 2014.

Avatar for Mathias Bynens

Mathias Bynens

March 01, 2014
Tweet

More Decks by Mathias Bynens

See All by Mathias Bynens
V8 internals for JavaScript developers @ Fronteers 2018
Avatar for Mathias Bynens mathiasbynens
3
500
V8 internals for JavaScript developers
Avatar for Mathias Bynens mathiasbynens
2
900
What’s new in ES2018?
Avatar for Mathias Bynens mathiasbynens
2
150
V8 internals for JavaScript developers
Avatar for Mathias Bynens mathiasbynens
1
170
Preventing timing attacks on the web @ Fronteers Jam 2016
Avatar for Mathias Bynens mathiasbynens
4
250
Front-End Performance: The Dark Side @ ColdFront Conference 2016
Avatar for Mathias Bynens mathiasbynens
1
430
Hacking with Unicode in 2016
Avatar for Mathias Bynens mathiasbynens
15
15k
Front-End Performance: The Dark Side @ Fronteers Spring Conference 2016
Avatar for Mathias Bynens mathiasbynens
16
57k
3.14 things I didn’t know about CSS @ CSSConf.asia 2015
Avatar for Mathias Bynens mathiasbynens
4
1.1k

Other Decks in Programming

See All in Programming
複雑化したリポジトリをなんとかした話　pipenvからuvによるモノレポ構成への移行
Avatar for Satoshi Kaneyasu satoshi256kbyte
1
770
詳しくない分野でのVibe Codingで困ったことと学び/vibe-coding-in-unfamiliar-area
Avatar for shibayu36 shibayu36
3
4.4k
開発者への寄付をアプリ内課金として実装する時の気の使いどころ
Avatar for Yunosuke Sakai ski
0
350
iOSエンジニア向けの英語学習アプリを作る！
Avatar for yukawashouhei yukawashouhei
0
180
10年もののAPIサーバーにおけるCI/CDの改善の奮闘
Avatar for masato hommaru mbook
0
780
GraphQL×Railsアプリのデータベース負荷分散 - 月間3,000万人利用サービスを無停止で
Avatar for Koya Masuda koxya
1
1.1k
iOSアプリの信頼性を向上させる取り組み/ios-app-improve-reliability
Avatar for yuki shinohara shino8rayu9
0
150
育てるアーキテクチャ：戦い抜くPythonマイクロサービスの設計と進化戦略
Avatar for fujidomoe fujidomoe
1
150
CSC305 Lecture 04
Avatar for Javier Gonzalez-Sanchez javiergs
PRO
0
250
私達はmodernize packageに夢を見るか feat. go/analysis, go/ast / Go Conference 2025
Avatar for m_t_tion1 kaorumuta
2
490
overlayPreferenceValue で実現する ピュア SwiftUI な AdMob ネイティブ広告
Avatar for Takashi uhucream
0
110
CSC509 Lecture 02
Avatar for Javier Gonzalez-Sanchez javiergs
PRO
0
410

Featured

See All Featured
"I'm Feeling Lucky" - Building Great Search Experiences for Today's Users (#IAC19)
Avatar for Dan Newman danielanewman
229
22k
GraphQLとの向き合い方2022年版
Avatar for Yosuke Kurami quramy
49
14k
Making the Leap to Tech Lead
Avatar for Ryan Cromwell cromwellryan
135
9.5k
Speed Design
Avatar for Sergey Chernyshev sergeychernyshev
32
1.1k
Understanding Cognitive Biases in Performance Measurement
Avatar for Philip Tellis bluesmoon
29
2.6k
Building Applications with DynamoDB
Avatar for Matt Wood mza
96
6.6k
Site-Speed That Sticks
Avatar for Harry Roberts csswizardry
11
880
How To Stay Up To Date on Web Technology
Avatar for Chris Coyier chriscoyier
791
250k
Statistics for Hackers
Avatar for Jake VanderPlas jakevdp
799
220k
Rebuilding a faster, lazier Slack
Avatar for samanthasiow samanthasiow
84
9.2k
We Have a Design System, Now What?
Avatar for Morgane Peng morganepeng
53
7.8k
Let's Do A Bunch of Simple Stuff to Make Websites Faster
Avatar for Chris Coyier chriscoyier
507
140k

Transcript

  1. @mathias · #kodio_2014 Ten things I didn’t know about HTML

  2. @mathias

  3. Ten things I didn’t know about HTML @mathias · #kodio_2014

  4. ∞ things I didn’t know about HTML, CSS & JavaScript

    @mathias · #kodio_2014

  5. Back to the ’90s kickin’ it old skool

  6. None

  7. Background colors <body bgcolor="pink"></body>

  8. Background colors <body bgcolor="pink"></body>

  9. Background colors <body bgcolor="#ffc0cb"></body>

  10. Background colors <body bgcolor="ffc0cb"></body>

  11. Background colors <body bgcolor="#f3f"></body> " #FF33FF

  12. Background colors <body bgcolor="f3f"></body> " #0F030F

  13. Background colors <body bgcolor="sick"></body> " #00C000

  14. Background colors <body bgcolor="MrT"></body> " #000000

  15. Background colors <body bgcolor="chucknorris"></body> " #C00000

  16. Background colors <body bgcolor="crap"></body> " #C0A000

  17. Background colors <body bgcolor="!"></body> " #000000

  18. Background colors <body bgcolor="kodio"></body> " #00D000

  19. Background colors http://mths.be/bgcolor

  20. Background colors http://mths.be/bgcolor

  21. “Valid HTML” conformance criteria

  22. Document Type Definition

  23. DTD <head> <p>Lorem ipsum.</p> </head>

  24. DTD <kitchensink>

  25. DTD fail <input type="date" placeholder="foo">

  26. DTD fail <input type="date" placeholder="foo"> <table> <tr><td>foo</td></tr> <tr><td colspan="2">bar</td></tr> </table>

  27. DTD fail <input type="date" placeholder="foo"> → can still be checked

    by a computer <table> <tr><td>foo</td></tr> <tr><td colspan="2">bar</td></tr> </table>

  28. Computer says no <img src="foo.png" alt=""> <time datetime="2013-10-03">LOL</time> <blockquote>not a

    quote</blockquote>

  29. Computer says no <img src="foo.png" alt=""> → can only be

    checked by a human <time datetime="2013-10-03">LOL</time> <blockquote>not a quote</blockquote>

  30. Take-away Don’t obsess about HTML validation. • not the whole

    story • validators have bugs, too Functionality trumps validation anyway.
 <meta http-equiv="X-UA-Compatible" content="IE=edge">

  31. Character references aka. “entities”

  32. Character references <!-- valid and reliable: --> <p>foo &amp; bar</p>

    <!-- renders as “foo & bar” -->

  33. ;

  34. github:twbs/bootstrap#3057

  35. github:twbs/bootstrap#3057

  36. ;

  37. ; PRETENDS TO BE OPTIONAL BREAKS STUFF WHEN OMITTED

  38. Character references <!-- valid and reliable: --> <p>foo &amp; bar</p>

    <!-- renders as “foo & bar” -->

  39. Character references <!-- invalid, but reliable: --> <p>foo &amp bar</p>

    <!-- renders as “foo & bar” -->

  40. Character references <!-- invalid, and confusing: --> <p title="foo&ampbar"> foo&ampbar

    </p> <!-- title renders as “foo&ampbar” --> <!-- text renders as “foo&bar” -->

  41. Character references <!-- valid and reliable: --> <p>foo & bar</p>

    <!-- renders as “foo & bar” --> http://mths.be/bdu

  42. Character references <!-- valid and reliable: --> <p>foo &gt; bar</p>

    <!-- renders as “foo > bar” -->

  43. Character references <!-- invalid, but reliable: --> <p>foo &gt bar</p>

    <!-- renders as “foo > bar” -->

  44. Character references <!-- invalid, and confusing: --> <p title="foo&gtbar"> foo&gtbar

    </p> <!-- title renders as “foo&gtbar” --> <!-- text renders as “foo>bar” -->

  45. Character references <!-- valid and reliable: --> <p>foo > bar</p>

    <!-- renders as “foo > bar” -->

  46. Character references <p>foo&#x85;bar</p> <!-- which symbol is this? --> <!--

    how will it render? -->

  47. Character references <p>foo&#x85;bar</p> <!-- which symbol is this? --> <!--

    how will it render? -->

  48. &#x85; is U+0085, right?

  49. &#x85; is U+0085, right? ✘

  50. Nope, not in HTML!

  51. Nope, not in HTML!

  52. …but it is in XHTML

  53. Character references

  54. Tags

  55. Valid HTML <!DOCTYPE html>
 <html>
 <head>
 <title>Foo</title>
 </head>
 <body>
 …


    </body>
 </html>

  56. Valid HTML <!DOCTYPE html>
 <html>
 <head>
 <title>Foo</title>
 </head>
 <body>
 …


    </body>
 </html>

  57. Valid HTML <!DOCTYPE html>
 <html>
 <head>
 <title>Huh?</title>
 <body>
 …


  58. Valid HTML <!DOCTYPE html>
 <html>
 <head>
 <title>Huh?</title>
 <body>
 …


  59. Valid HTML <!DOCTYPE html>
 <title>lolwut</title>
 …


  60. None
  61. None

  62. ^ n FTFY

  63. Using CSS without HTML

  64. None
  65. None

  66. CSS without HTML $ curl -i http://mathiasbynens.be/demo/css-without-html HTTP/1.1 200 OK

    Date: Wed, 03 Oct 2013 13:33:37 GMT Link: <css-without-html.css>;rel=stylesheet Content-Length: 0 Content-Type: text/html; charset=UTF-8 http://mths.be/bpe

  67. CSS without HTML $ curl -i http://mathiasbynens.be/demo/css-without-html HTTP/1.1 200 OK

    Date: Wed, 03 Oct 2013 13:33:37 GMT Link: <css-without-html.css>;rel=stylesheet Content-Length: 0 Content-Type: text/html; charset=UTF-8 http://mths.be/bpe
  68. None

  69. Font family names

  70. CSS html {
 font-family: 'Comic Sans MS';
 } “If there’s

    whitespace in the font family name, it must be quoted.”

  71. CSS html {
 font-family: Comic Sans MS;
 } “If there’s

    whitespace in the font family name, it must be quoted.” http://mths.be/bft

  72. CSS html {
 font-family: 456bereastreet;
 }

  73. CSS html {
 font-family: 456bereastreet;
 }

  74. CSS html {
 font-family: \34 56bereastreet;
 }

  75. CSS html {
 font-family: \34 56bereastreet;
 }

  76. CSS html {
 font-family: '456bereastreet';
 }

  77. CSS http://mths.be/bjm

  78. Attribute values

  79. Attribute values <a href="foo">…</a> <style> a[href="foo"] { background: hotpink; }

    </style>

  80. Attribute values <a href=foo>…</a> <style> a[href=foo] { background: hotpink; }

    </style>

  81. Attribute values <a href=foo|bar>…</a> <style> a[href=foo|bar] { background: hotpink; }

    </style>

  82. Attribute values <a href=foo|bar>…</a> <style> a[href=foo|bar] { background: hotpink; }

    </style>

  83. Attribute values <a href=foo|bar>…</a> <style> a[href="foo|bar"] { background: hotpink; }

    </style> http://mths.be/bal

  84. Attribute values http://mths.be/bjn

  85. Handling user input

  86. http://mths.be/bqv

  87. http://mths.be/bqv

  88. Characters in JS

  89. JavaScript string length >> 'A'.length // U+0041 1 >> 'A'

    == '\u0041' true >> 'B'.length // U+0042 1 >> 'B' == '\u0042' true

  90. String length ≠ char count >> 'A'.length // U+1D400 2

    >> 'A' == '\uD835\uDC00' true >> 'B'.length // U+1D401 2 >> 'B' == '\uD835\uDC01' true http://mths.be/bed

  91. Surrogate pairs // for non-BMP code points (> 0xFFFF) function

    getSurrogates(codePoint) { var high = Math.floor((codePoint - 0x10000) / 0x400) + 0xD800; var low = (codePoint - 0x10000) % 0x400 + 0xDC00; return [ high, low ]; } ! function getCodePoint(high, low) { var codePoint = (high - 0xD800) * 0x400 + low - 0xDC00 + 0x10000; return codePoint; } ! >> getSurrogates('A'); // U+1D400 [ 0xD835, 0xDC00 ] >> getCodePoint(0xD835, 0xDC00); 0x1D400 http://mths.be/bed

  92. JS string character count function countSymbols(string) { return punycode.ucs2.decode(string).length; }

    ! >> countSymbols('A') // U+0041 1 >> countSymbols('A') // U+1D400 1 http://mths.be/punycode

  93. JS variable names

  94. Which is invalid? var H ̹̙̦̮͉̩̗̗ ͧ̇̏̊̾ Eͨ͆͒̆ͮ̃ ͏̷̮̣̫̤̣Cͯ̂͐ ͏̨̛͔̦̟͈̻O

    ̜͎͍͙͚̬̝̣ ̽ͮ͐͗̀ͤ̍̀ ͢ M̴̡̲̭͍͇̼̟̯̦ ̉̒͠ Ḛ̛̙̞̪̗ ͥ ͤͩ̾͑̔͐ ͅ Ṯ̴̷̷̗̼͍ ̿̿̓̽͐ H ̙̙ ̔̄ ͜ ; var "_ಠಠ_"; var ໦ϗ îਓƎ ℵೋീΔେ; var ʃː λ ˀπ ᐩᐨᐟᑉᐦᐸᐳ\u200C; var a; http://mths.be/ber

  95. ♥ JS var H ̹̙̦̮͉̩̗̗ ͧ̇̏̊̾ Eͨ͆͒̆ͮ̃ ͏̷̮̣̫̤̣Cͯ̂͐ ͏̨̛͔̦̟͈̻O ̜͎͍͙͚̬̝̣

    ̽ͮ͐͗̀ͤ̍̀ ͢ M̴̡̲̭͍͇̼̟̯̦ ̉̒͠ Ḛ̛̙̞̪̗ ͥ ͤͩ̾͑̔͐ ͅ Ṯ̴̷̷̗̼͍ ̿̿̓̽͐ H ̙̙ ̔̄ ͜ ; // valid var !_ಠಠ_!; // valid var ໦ϗ îਓƎ ℵೋീΔେ; // valid var ʃː λ ˀπ ᐩᐨᐟᑉᐦᐸᐳ\u200C; // valid var a; // syntax error http://mths.be/ber

  96. /^(?!(?:do|if|in|for|let|new|try|var|case|else| enum|eval|false|null|this|true|void|with|break| catch|class|const|super|throw|while|yield|delete| export|import|public|return|static|switch|typeof| default|extends|finally|package|private|continue| debugger|function|arguments|interface|protected| implements|instanceof)$)[$A-Z\_a-z\xaa\xb5\xba \xc0-\xd6\xd8-\xf6\xf8-\u02c1\u02c6-\u02d1\u02e0- \u02e4\u02ec\u02ee\u0370- \u0374\u0376\u0377\u037a-\u037d\u0386\u0388-

    \u038a\u038c\u038e-\u03a1\u03a3-\u03f5\u03f7- \u0481\u048a-\u0527\u0531-\u0556\u0559\u0561- \u0587\u05d0-\u05ea\u05f0-\u05f2\u0620-\u064a

  97. \u20f0\u2cef-\u2cf1\u2d7f\u2de0-\u2dff\u302a- \u302f\u3099\u309a\ua620-\ua629\ua66f\ua674- \ua67d\ua69f\ua6f0\ua6f1\ua802\ua806\ua80b\ua823- \ua827\ua880\ua881\ua8b4-\ua8c4\ua8d0- \ua8d9\ua8e0-\ua8f1\ua900-\ua909\ua926-\ua92d \ua947-\ua953\ua980-\ua983\ua9b3-\ua9c0\ua9d0- \ua9d9\uaa29-\uaa36\uaa43\uaa4c\uaa4d\uaa50- \uaa59\uaa7b\uaab0\uaab2-\uaab4\uaab7\uaab8\uaabe \uaabf\uaac1\uaaeb-\uaaef\uaaf5\uaaf6\uabe3- \uabea\uabec\uabed\uabf0-\uabf9\ufb1e\ufe00-

    \ufe0f\ufe20-\ufe26\ufe33\ufe34\ufe4d-\ufe4f \uff10-\uff19\uff3f]*$/

  98. JS variable names http://mths.be/bjo

  99. Questions? @mathias