It’s been 7 months since the last post in my YSlow series. So why did I stop blogging about performance optimization? Well, actually there are two answers to that question. First is because of my passion for unit-testing, which I started blogging about at pretty much that time. Secondly,…
A former college of mine told me, that he had founded “The association opposed the abandonment of PerformanceDude.com”. In order to make him happy, I thought that I would leave the wonderful world of unit testing for a moment, in the benefit of writing a performance related post 🙂 We’…
Way down the list of YSlow rules, we’ve reached rule number 11, which is important and a no-brainer to implement. The rule is titled “Minify JavaScript and CSS.” So what is minification, and why do we need it? Both JavaScript and CSS files are packed with unnessecary characters like…
Most of us (me included) don’t think much about the way DNS works. Browsers, on the other hand, use DNS pretty much every day. For the uninformed, I will start by explaining how DNS works. If you already know this, feel free to skip the following paragraph. As you…
We’ve briefly touched this subject a number of times already. Making your JavaScript and CSS external simply means moving it from your HTML header to their own files, referenced as an external file in the header. So why does Yahoo think that this is a good idea? We’ve…
Time for another YSlow rule. This week we will be looking at rule number 8—avoid CSS expressions. My knowledge about CSS is very limited, and I’ve always seen CSS as a format for specifying style information rather than an actual programming language. It turns out that you can…
Last week I blogged about Google making Page Speed available for Chrome users. This week Google surprises me again, by doing Page Speed Online. Page Speed Online is pretty much just an online edition of Page Speed for Firefox and Chrome. The funny thing is, that I just a couple…
We all know it: zipping is a great way to compress the size of a file. This rule also applies on the web. Zipping responses from a server is natively implemented in the HTTP version 1.1 standard, which is why you don’t have any excuse left not to…
We have reached rule number 4 in our journey into the exciting world of the YSlow rule set. Rule number 4 is all about caching. We have tackled the caching area a bit in some of the previous posts, but in this post I will dig more into this important…
In this post I will try to explain to you the idea behind a content delivery network or CDN. I think that the Yahoo documentation on this rule is a bit confusing. So here’s my attempt to explain YSlow rule #2: use a content delivery network. To explain the…