What tends to be the worst performance hog for websites?
The YSlow site often mentions the number of HTTP requests as a major factor, but aside from that. Steve: The average YSlow score across the top Alexa sites has moved from F to D. That’s not great, but I believe the performance best practices from my book are gradually taking hold. Looking ahead, JavaScript is going to be the main performance bottleneck going forward. Web 2.0 is taking off, and the amount of JavaScript in popular web sites is growing. Furthermore, JavaScript is parsed and executed on 100% of page views, regardless of the state of the browser’s cache. The first three chapters from my next book, and the contents of my last few conference appearances, focus on performance best practices for JavaScript. Pingdom: In your opinion, which is the most overlooked optimization technique for websites? Steve: The easiest performance improvements to make that are often overlooked are adding a far future Expires header and turning on compression. Slightly more difficult but something
