Required Reading: Yahoo Research on Mobile Cache Size

With more and more people embracing the idea of producing HTML5 mobile web apps, research like this is becoming vital. There are a lot of gotchas in this article, especially if you’ve been ignoring this space.

You should read the whole article, but I just want to point out a pair of findings before I send you on your way. One has been a known issue for a while (it’s a ySlow rule, after all,) but it’s still worth pointing out. The other… wow… my emphasis.

Results varied wildly across the three most recent versions of iOS. Astonishingly, Mobile Safari on iOS 3.1.3 did not cache components of any size, despite having an apparently unlimited page cache size. This is troubling since it means iOS 3.1.3 users are likely getting a suboptimal browsing experience, especially if they aren’t using wifi. The unlimited page cache size does little good here, since it only comes into play for back/forward navigations. This behavior is a significant change from what others observed in previous iOS releases and I can’t imagine any good reason for it, so I suspect this may be a bug.

Mobile Safari on iOS 3.2 (which is only available on the iPad) does not exhibit this bug. Its 25.6KB component limit and ~281.6KB total cache limit are better than nothing, but they still seem paltry compared to the other devices tested. Uniquely among iOS devices, the iPad appears to limit the size of pages in the page cache to 25.6KB, the same as its component size limit.

Read the rest of the article:

Mobile Browser Cache Limits: Android, iOS, and webOS

Performance Tip: When Linking to JavaScript on the Google Ajax Library CDN, Use a Specific Version Number

I’ve seen this a few times over the past few months:

<script type="text/javascript" src=""></script> 

What that basically says to Google is “give me the latest 1.* branch version of jQuery and make sure it’s minified.”
Continue reading “Performance Tip: When Linking to JavaScript on the Google Ajax Library CDN, Use a Specific Version Number”

Why Do I Like Web Performance? For One Thing, it’s Easier to Measure Success

One of the reasons I’m drawn to the performance side of the business is that it’s one of the few pieces of of your site or application where you can really know when you’re doing the right thing.

There are a lot of questions that can run through your head during a site build. Is the design right? How about the feature set? do these labels make sense? Is the language correct for my audience? Does this visualization truly illustrate the underlying data and add meaning? Was I right to use canvas? Should we be using web storage?

Those (and many other examples) are the things that can (and should) your thoughts. You can leverage experience and best practices throughout, but there are always mistakes, miscommunications and surprises waiting around the corner, so sweating the details of a design or interaction model can make or break an application.

One aspect that brings a little bit of certainty is the question of speed.

The site is either fast, or it isn’t.

There are certainly degrees of “fast,” a full featured application won’t be as fast as, but once you’ve defined a speed goal there are plenty of ways to know if you’re hitting your marks which makes it a bit more satisfying than the stuff that’s a little more nebulous (or takes a little longer) to measure.

Front End Performance for the Common Man: Practical Strategies to Speed Up Your Site

Front End Performance for the Common Man: Practical Strategies to Speed Up Your Site from rob larsen on Vimeo.

Follow along with the presentation. (PowerPoint presentation)

Here’s the sample ant build script referenced in the deck. (Zip file)

And here’s the article mentioned in one of the early slides:
Why Front End Performance Matters to Everyone, Not Just the High Traffic Giants