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Como Perder Peso (no browser)
Zeno Rocha
March 09, 2013
Technology
52
10k
Como Perder Peso (no browser)
Presented at Rio.JS Conf
March 9, 2013
Rio de Janeiro, Brazil
Zeno Rocha
March 09, 2013
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Transcript
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hoje vamos falar de performance
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“Otimize a performance do front-end primeiro, é onde 80/90% do
tempo de resposta ao usuário é gasto.” - Steve Souders
http://googlewebmastercentral.blogspot.com.br/2010/04/using-site-speed-in-web-search-ranking.html
None
• Economizar 1kb significa: • Em 60 segundos = 3.4GB
Fonte: http://jaydson.org/talks/x-web-performance/
• Economizar 1kb significa: • Em 1 hora = 180GB
Fonte: http://jaydson.org/talks/x-web-performance/
• Economizar 1kb significa: • Em 1 dia = 4.2TB
Fonte: http://jaydson.org/talks/x-web-performance/
None
• + 15.000.000 de acessos por dia • De 3mb
para 267kb • De 7.5s para 4.3s Fonte: http://www.slideshare.net/keppelen/performance-frontend-front-in-macei/
• Diminuir 3.2s resultou em: • Redução de custo em
servidores de R$ 16.000,00 por dia Fonte: http://www.slideshare.net/keppelen/performance-frontend-front-in-macei/
• Diminuir 3.2s resultou em: • Aumento de receita de
R$ 1.000.000,00 por dia Fonte: http://www.slideshare.net/keppelen/performance-frontend-front-in-macei/
html CSS imagens servidor jquery JS
None
html
#27 evite códigos inline
inline #27 <style> .center { width: 960px; margin: 0 auto;
} </style> - requisições +tamanho
externo #27 <link rel="stylesheet" href="main.css"> + organização - tamanho +
cache
#26 estilos no topo, scripts no rodapé
#26 <!doctype html> <html> <head> <meta charset="UTF-8"> <title>Browser Diet</title> <!--
CSS --> <link rel="stylesheet" href="style.css"> </head>
#26 <body> <p>Lorem ipsum dolor sit amet.</p> <!-- JS -->
<script src="script.js"></script> </body> </html>
comprima seu html #25
normal #25 <p>Lorem ipsum dolor sit amet.</p> <!-- My List
--> <ul> <li><a href="#"></a></li> <li><a href="#"></a></li> <li><a href="#"></a></li> </ul>
#25 <p>Lorem ipsum dolor sit amet.</ p><ul><li><a href="#"></a></li><li><a href="#"></a></li><li><a href="#"></a></
li></ul> comprimido
https://code.google.com/p/htmlcompressor/
https://github.com/jney/grunt-htmlcompressor
#24 experimente async & defer
#24 script normal <script src="example.js"></script>
#24 script async <script async src="example.js"></script> +ie10
#24 script defer <script defer src="example.js"></script> +ie5
CSS
comprima seu css #23
normal #23 .center { width: 960px; margin: 0 auto; }
/* --- Structure --- */ .intro { margin: 100px; }
#23 comprimido .center{width:960px;margin:0 auto;}.intro{margin: 100px;position:relative;}
http://yui.github.com/yuicompressor/
http://www.cssminifier.com/
https://github.com/jzaefferer/grunt-css
combine vários arquivos em um só #22
#22 <link rel="stylesheet" href="structure.css"> <link rel="stylesheet" href="banner.css"> <link rel="stylesheet" href="layout.css">
<link rel="stylesheet" href="component.css"> <link rel="stylesheet" href="all.css"> vs
http://yui.github.com/yuicompressor/
http://www.cssminifier.com/
https://github.com/jzaefferer/grunt-css
não use seletor universal #21
* { margin: 0; padding: 0; border: none; text-decoration: none;
outline: 0; } #21
http://meyerweb.com/eric/tools/css/reset/
http://necolas.github.com/normalize.css/
prefira <link> ao @import #20
<link rel="stylesheet" href="style.css"> #20 vs @import url('style.css');
pense e repense seu key selector #19
key selector >> a header nav ul li a {}
#19
key selector header nav ul li * { /* Péssimo
*/ } header nav ul li a { /* Muito Ruim */ } nav a { /* Ruim */ } nav a.nav-link { /* Bom */ } nav .nav-link { /* Ótimo */ } .nav-link { /* Excelente */ } #19
JAVASCRIPT
códigos de terceiros? sempre assíncronos #18
async var script = document.createElement('script'), scripts = document.getElementsByTagName('script')[0]; script.async =
true; script.src = url; scripts.parentNode.insertBefore(script, #18
guarde o tamanho do array #17
ruim... var arr = new Array(1000); for (var i =
0; i < arr.length; i++) { // O tamanho do array é calculado 1000 } #17
bom! var arr = new Array(1000); for (var i =
0, len = arr.length; i < len; i++) { // O tamanho só é calculado 1 vez e armazenado } #17
http://jsperf.com/browser-diet-cache-array-length
http://jsperf.com/browser-diet-cache-array-length
evite o document.write #16
html5 boilerplate <script src="//ajax.googleapis.com/ajax/libs/ jquery/1.9.0/jquery.min.js"></script> <script>window.jQuery || document.write('<script src="js/vendor/jquery-1.9.0.min.js"><\/ script>')</script>
#16
minimize repaints e reflows #15
ruim... var myList = document.getElementById("myList"); for (var i = 0;
i < 100; i++) { myList.innerHTML += "<span>" + i + "</span>"; } #15
var myList = ""; for (var i = 0; i
< 100; i++) { myList += "<span>" + i + "</span>"; } document.getElementById("myList").innerHTML = myList; bom! #15
http://jsperf.com/browser-diet-dom-manipulation
http://jsperf.com/browser-diet-dom-manipulation
comprima seu js #14
normal #14 BrowserDiet.app = function() { var foo = true;
return { bar: function() { // do something } }; };
comprimido BrowserDiet.app=function() {return{bar:function(){}}}; #14
http://yui.github.com/yuicompressor/
https://developers.google.com/closure/compiler/?hl=pt
https://github.com/mishoo/UglifyJS
combine vários arquivos em um só #13
#13 <script src="navbar.js"></script> <script src="component.js"></script> <script src="page.js"></script> <script src="framework.js"></script> <script
src="all.js"></script> vs
http://gruntjs.com/
jquery
use sempre a última versão #12
<script src="http://code.jquery.com/jquery-latest.js"></script> #12 vs <script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
seletores #11
#11 find children .class #id context
#11 $("#foo"); id é mais rapido
http://jsperf.com/browser-diet-jquery-selectors
http://jsperf.com/browser-diet-jquery-selectors
abuse do encadeamento #10
não encadeando $("#object").addClass("foo"); $("#object").css("border-color","#f0f"); $("#object").width(200); $("#object").removeClass("bar"); #10
encadeando $("#object").addClass("foo").css("border-color", "#ccc").width(200).addClass("bar"); #10
http://jsperf.com/browser-diet-chaining
http://jsperf.com/browser-diet-chaining
use for ao invés de each #9
#9 while reverso for $.each for in
#9 for ( var i = 0, len = a.length;
i < len; i++ ) { e = a[i]; } for é mais rapido
http://jsperf.com/browser-diet-jquery-each-vs-for-loop
http://jsperf.com/browser-diet-jquery-each-vs-for-loop
não use jquery #8
jquery $('a').on('click', function() { console.log( $(this).attr('id') ); }); #8
js puro $('a').on('click', function() { console.log( this.id ); }); #8
http://jsperf.com/browser-diet-this-attr-id-vs-this-id
http://jsperf.com/browser-diet-this-attr-id-vs-this-id
imagens
css sprites #7
imagem #7
css #7 .icon-foo { background-image: url('mySprite.png'); background-position: -10px -10px; }
.icon-bar { background-image: url('mySprite.png'); background-position: -5px -5px; }
http://wearekiss.com/spritepad
http://www.spritecow.com/
http://compass-style.org/help/tutorials/spriting/
não escale as imagens direto no código #6
html #6 <img width="100" height="100" src="logo.jpg" alt="Logo">
otimize as imagens #5
#5 lossless png 8 png 24 jpg gif
servidor
habilite o caches dos arquivos #4
.htaccess #4 ExpiresActive On ExpiresByType image/gif "access plus 6 months"
ExpiresByType image/jpeg "access plus 6 months" ExpiresByType image/png "access plus 6 months" ExpiresByType text/css "access plus 6 months" ExpiresByType text/javascript "access plus 6 months"
gzip #3
.htaccess #3 AddOutputFilterByType DEFLATE text/html AddOutputFilterByType DEFLATE text/plain AddOutputFilterByType DEFLATE
text/xml AddOutputFilterByType DEFLATE text/css AddOutputFilterByType DEFLATE application/javascript
bonus ^
ferramentas de análise #2
http://yslow.org/
https://developers.google.com/speed/pagespeed/insights_extensions?hl=pt-BR
http://www.webpagetest.org/
performance deve ser pensada no projeto como um todo
e não só deixar pra testar no finalzinho
lembre-se
o preguiçoso trabalha dobrado
quero aprender mais, aonde eu vou?
None
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https://developers.google.com/speed/docs/best-practices/rules_intro
http://developer.yahoo.com/performance/rules.html
nada em português?
e se a gente juntasse...
renato mangini - google
sérgio lopes - caelum
mike taylor - opera
marcel duran - twitter
“Pica voando das galáxias criado em cativeiro” browserdiet.com/pt
“Pica voando das galáxias criado em cativeiro” - Bernard de
Luna
“Pica voando das galáxias criado em cativeiro” - Bernard de
Luna
2º Encontro - 2011
fim. zenorocha.com browserdiet.com #1