The document discusses techniques for optimizing websites to load faster. It provides 12 tips for optimization including enabling GZIP compression, minifying JavaScript and CSS, optimizing image sizes and formats, reducing the number of requests, and combining files. Performance statistics are given showing how even small reductions in load times can significantly increase user engagement and sales.

1. por uma web
mais rápida:
técnicas de
otimização
de sites

2. Sérgio Lopes
sergio.lopes
@caelum.com.br
facebook.com/
sergio.caelum
@sergio_caelum

3. Post completo
sobre a palestra:
http://bit.ly/n0e40x

4. Por que você
deve otimizar
seu Site?

5. esperar
é
muito
muito
irritante!

6. esperar
é
muito
muito
irritante!

7. Para c ada 400ms de melhora,
o tráfe go do Yahoo! aumenta 9%

8. Ao diminuir 2.2s de sua
landing page, a Mozilla
aumentou em 15% os
downloads do Firefox.

9. 100ms de melhora aumentam o
faturamento da Amazon em 1%

10. Um experimento do
Google aumentou o
número de resultados
de 10 para 30, indo
de 0.4s para 0.9s.
O tráfego caiu 20%.

11. 2s a mais na busca do Bing
diminuíram o faturamento em 4.3%

12. Tamanho: de 100kb para 300kb
Requests: de 12 para 42
Carregamento: de 2s para 6s

13. queda de
21% no time on site,
28% nos pageviews e
18% no conversion rate

15. média de
9s para
carregar
a página

16. 75% demoram 400ms
ou menos no servidor

17. “ Diminua
o tamanho
dos requests

18. #1 Habilite GZIP

19. 43% dos
requests
sem GZIP

20. #2 Minifique JavaScript

21. só13%
comprimiram
todos os
JavaScripts

22. #3 Minifique CSS

23. #4 Comprima HTML

24. #5 Não redimensione imagens no HTML

25. #6 Otimize as imagens

26. 22%
economizariam
mais de 40%

27. #7 Pense no formato das imagens

28. PNG
JPG
GIF

29. PNG Alpha
JPG
GIF

30. PNG Alpha
JPG Lossy
GIF

31. PNG Alpha
JPG Lossy
GIF Animações

32. PNG8
PNG Alpha
PNG32
JPG Lossy
GIF Animações

33. #8 Diminua cookies e headers

34. “ Diminua
a quantidade
de requests

35. #9 Junte arquivos JavaScript

36. média de10
arquivos
JavaScript

37. #10 Junte arquivos CSS

38. média de5
arquivos CSS

39. #11 Use Sprites

41. metade tem
36
mais de
imagens

42. #12 Use Data URIs

43. <img width="160" height="50" alt="Logo Caelum"
src="logo_caelum.png" />

44. <img width="160" height="50" alt="Logo Caelum"
src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAA
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"/>

45. #13 Configure os headers

46. 87% fazem
mais que 10
requests no
2º pageview

47. #14 Tire firulas do design

48. “
Performance é
medida pela
percepção do
usuário

49. #15 Especifique o tamanho das imagens

50. #16 Coloque o JavaScript no fim

51. média até
mostrar
alguma coisa é
4.3s

52. #17 Coloque o CSS no topo

55. #18 Adie o carregamento do que puder

59. #19 Abuse do carregamento assíncrono

60. <script type="text/javascript">
var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-123456']);
_gaq.push(['_trackPageview']);
(function() {
var ga = document.createElement('script');
ga.type = 'text/javascript';
ga.async = true;
ga.src = ('https:' == document.location.protocol ?
'https://ssl':'http://www') + '.google-analytics.com/ga.js';
var s = document.getElementsByTagName('script')[0];
s.parentNode.insertBefore(ga, s);
})();
</script>

61. #20 Otimize o First-View

62. #21 Design performático

63. N U S
B Ô
! !!

64. #22 Automatize

65. #23 Use ferramentas de diagnóstico

66. #24 Pré-carregue componentes

67. #25 Escreva código eficiente

68. #26 Dispare logo o onload

70. Diminua
o tamanho
dos requests

71. Diminua
o tamanho
dos requests
S
Diminua
a quantidade
de requests

72. Diminua Priorize
o tamanho carregamento
dos requests e renderização
S
Diminua
a quantidade
de requests

73. Diminua Priorize
o tamanho carregamento
dos requests e renderização
S
S
Diminua Performance é
a quantidade medida pela
de requests percepção do
usuário

74. #1 Fácil e rápido, faça já!
#2 Importante, mas não trivial
#3 Desafiador e eficaz

75. Obrigado!
sergio.lopes
@caelum.com.br
facebook.com/
sergio.caelum
@sergio_caelum

76. Post completo
sobre a palestra:
http://bit.ly/n0e40x