Book Review: High Performance JavaScript

Posted on by Rob Larsen

I read High Performance JavaScript when it came out. It took me a while to write this review.

I’ve been busy (day job x spending a lot of time outside because it’s summer = less time for writing)

Anyway, it’s really good. It’s short, but well-written and focused so it’s an easy book to dive into, digest and integrate into your day-to-day.

One of the things I liked about it is that the topics cover enough ground that even as an experienced/expert developer you can learn some things that you’ve probably never run into in a production environment. Maybe you haven’t dealt with a lot of heavy-duty string manipulation and regular expressions or possibly you haven’t done a ton with build systems. They’re covered here, by experts. You might not be an expert after reading it, but you’ll definitely have enough to go on to start working in some solid enhancements into your own code.

All in all, this is a recommended book for all intermediate to expert JavaScript developers. It will get you thinking about your own code, about convenience and about JavaScript performance in a very fundamental way. That’s good for you, for your users and for the web as a whole.

I’m Going to Enjoy Writing Code for Internet Explorer 9 (I Can’t Believe I Just Typed Those Words)

Posted on by Rob Larsen

In case you missed it the latest Internet Explorer 9 Platform Preview is out and it’s a thing of beauty. It added Canvas support so the first thing I did was run it through some demo code. It’s faster than Chrome. Visibly faster. No benchmarks needed. It’s such an incredible difference from the current Internet Explorer family which are many times slower than the good browsers out there.

The good news doesn’t stop there. There’s actual standards support.

PPK enthuses:

In the past few days I’ve been revising the CSS compatibility table with information about the latest crop of browsers. There’s no doubt about it: this is IE9’s show. It just supports nearly everything. No hassle, no buts.

And then enthuses some more:
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Required Reading: Yahoo Research on Mobile Cache Size

Posted on by Rob Larsen

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

Posted on by Rob Larsen

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


<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>

What that basically says to Google is “give me the latest 1.* branch version of jQuery and make sure it’s minified.”
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