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

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

Mathias Bynens
March 01, 2014
Programming
10
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.

Mathias Bynens

March 01, 2014
Tweet

More Decks by Mathias Bynens

See All by Mathias Bynens
V8 internals for JavaScript developers @ Fronteers 2018
mathiasbynens
2
470
V8 internals for JavaScript developers
mathiasbynens
1
760
What’s new in ES2018?
mathiasbynens
1
110
V8 internals for JavaScript developers
mathiasbynens
0
130
Preventing timing attacks on the web @ Fronteers Jam 2016
mathiasbynens
3
220
Front-End Performance: The Dark Side @ ColdFront Conference 2016
mathiasbynens
0
350
Hacking with Unicode in 2016
mathiasbynens
14
14k
Front-End Performance: The Dark Side @ Fronteers Spring Conference 2016
mathiasbynens
15
57k
3.14 things I didn’t know about CSS @ CSSConf.asia 2015
mathiasbynens
3
910

Other Decks in Programming

See All in Programming
急成長期の品質とスピードを両立するフロントエンド技術基盤
soarteclab
0
930
創造的活動から切り拓く新たなキャリア 好きから始めてみる夜勤オペレーターからSREへの転身
yjszk
1
130
SymfonyCon Vienna 2025: Twig, still relevant in 2025?
fabpot
3
1.2k
rails stats で紐解く ANDPAD のイマを支える技術たち
andpad
1
290
RWC 2024 DICOM & ISO/IEC 2022
m_seki
0
210
range over funcの使い道と非同期N+1リゾルバーの夢 / about a range over func
mackee
0
110
[JAWS-UG横浜 #76] イケてるアップデートを宇宙いち早く紹介するよ！
maroon1st
0
460
Итераторы в Go 1.23: зачем они нужны, как использовать, и насколько они быстрые?
lamodatech
0
710
Jakarta EE meets AI
ivargrimstad
0
230
ゆるやかにgolangci-lintのルールを強くする / Kyoto.go #56
utgwkk
1
370
Monixと常駐プログラムの勘どころ / Scalaわいわい勉強会 #4
stoneream
0
270
20年もののレガシープロダクトに 0からPHPStanを入れるまで / phpcon2024
hirobe1999
0
270

Featured

See All Featured
Adopting Sorbet at Scale
ufuk
73
9.1k
Design and Strategy: How to Deal with People Who Don’t "Get" Design
morganepeng
127
18k
Building Flexible Design Systems
yeseniaperezcruz
327
38k
Producing Creativity
orderedlist
PRO
341
39k
Templates, Plugins, & Blocks: Oh My! Creating the theme that thinks of everything
marktimemedia
28
2.1k
How to train your dragon (web standard)
notwaldorf
88
5.7k
4 Signs Your Business is Dying
shpigford
181
21k
Visualization
eitanlees
146
15k
Distributed Sagas: A Protocol for Coordinating Microservices
caitiem20
330
21k
Intergalactic Javascript Robots from Outer Space
tanoku
270
27k
RailsConf 2023
tenderlove
29
940
10 Git Anti Patterns You Should be Aware of
lemiorhan
PRO
656
59k

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