Arquivo da categoria: javascript

Intercâmbio de dados sem as desvantagens do XML

Douglas Crockford, em seu artigo “JSON: The Fat-Free Alternative to XML”, exibe um comparativo entre os formatos para intercâmbio de dados JSON e XML, mostrando as vantagens da utilização do JSON (JavaScript ObjectNotation).

The most informed opinions on XML (see for example xmlsuck.org) suggest that XML has big problems as a data-interchange format, but the disadvantages are compensated for by the benefits of interoperability and openness.
JSON promises the same benefits of interoperability and openness, but without the disadvantages.

Symfony Cheat-Sheet – Helpers Javascript e Ajax


Continuando a publicação das referências sobre o framework symfony, esta segunda inicia a série sobre os helpers do symfony, trazendo uma visão geral das funções Javascript e Ajax que o framework possui.

Idiomas disponíveis:

  • Português – PDF
  • English – PDF
  • Français – PDF (Traduit par COil. Merci!)

page_word.png For translators (Word document with the cheat-sheet texts)

[Update – 01/01/2008] adicionada tradução para francês

Regras para otimizar a performance de sites web

As 14 regras, segundo Steve Souders (Chief Performance Yahoo!), para otimizar o desempenho de sites web:

  • Rule 1 – Make Fewer HTTP Requests
  • Rule 2 – Use a Content Delivery Network
  • Rule 3 – Add an Expires Header
  • Rule 4 – Gzip Components
  • Rule 5 – Put CSS at the Top
  • Rule 6 – Move Scripts to the Bottom
  • Rule 7 – Avoid CSS Expressions
  • Rule 8 – Make JavaScript and CSS External
  • Rule 9 – Reduce DNS Lookups
  • Rule 10 – Minify JavaScript
  • Rule 11 – Avoid Redirects
  • Rule 12 – Remove Duplicate Scripts
  • Rule 13 – Turn Off ETags
  • Rule 14 – Make AJAX Cacheable and Small

A otimização do Front-End é o fator chave para um alto desempenho:

There are three main reasons why front-end performance is the place to start.

  1. There is more potential for improvement by focusing on the front-end. Cutting it in half reduces response times by 40% or more, whereas cutting back-end performance in half results in less than a 10% reduction.
  2. Front-end improvements typically require less time and resources than back-end projects (redesigning application architecture and code, finding and optimizing critical code paths, adding or modifying hardware, distributing databases, etc.).
  3. Front-end performance tuning has been proven to work. Over fifty teams at Yahoo! have reduced their end-user response times by following our performance best practices, often by 25% or more.

Our performance golden rule is: optimize front-end performance first, that’s where 80% or more of the end-user response time is spent.