Web Performance Optimization Blog

Web performance optimization is abou making your site faster. It's important. Do it!

Win a free Velocity NYC conference pass!

A simple raffle and perhaps your last chance to win a 2-day pass for the great Web Performance and Operations conference (NYC, Oct 14-16)

Why loading third party scripts async is not good enough

Defer loading third party (async) scripts until after onload, for better, more meaningful page load time data.

Velocity Europe conference: 20% discount!

Come to the best Web Performance and Operations conference in Europe (Berlin, Nov 8-9). Register now for Velocity Europe with a 20% discount!

Google +1 Button Performance Review

The performance of the Google +1 Button is disappointing. It has a strong negative effect on page load time. I describe the problems and provide a (partly) solution.

Measure site speed on iPhone in The Netherlands

Test how fast your site loads on an iPhone in The Netherlands. You can even record a video to see how it loads!

Web Performance Quiz - win a free pass to Velocity 2011!

Want to win a free pass to the best Web Performance & Operations conference in the world, June 14-16 in Sillicon Valley? Play the Web Performance Quiz!

IE9 Performance Checklist

IE9 is different from IE8 when it comes to performance. This checklist sums up many (all?) IE9 specific performance issues and changes.

Prevent double callback execution in IE9

When loading a script dynamically, callback code may get executed twice in IE9, like in Steve Souders' Script Onload technique. The solution is simple.

Iframe loading techniques and performance

An overview of different ways to use an iframe for loading content, ads & widgets and how it affects site performance. Web devs: pay special attention to the Dynamic Asynch Iframe. It's awesome and you may have not heard about it before.

Non-blocking Google Adsense ads: improve page speed

A single Google Adsense ad increases page load time by approx. 0.4 seconds. Understand why and find out how to easily solve this problem, today.

Better @font-face performance: flushing the document early

Improve the perceived load time and user experience by sending the first part of the HTML document - with the @font-face declaration - to the browser early.
Note: this article needs an update. The concept is still valid, but it needs more testing.