Tag Archives: opera

New: cross-document messaging

With new versions of our trusted browsers coming out, web developers who like living on the edge can start  using some of the new features that are becoming available. One such goody is cross-document messaging, which is part of the HTML5 draft spec.

Cross-document messaging allows children of a window (think iframes, popups, …) to communicate using JavaScript, even if they originate from a different domain. This means that Instead of just iframing an external application, without being able to integrate further, your page can send and receive messages to/ from it. PostMessage could even be used to do cross-domain XHR (a hidden iframe on the same domain as a a remote datasource can be used as a proxy to perform XmlHttpRequests on that remote domain) untill the real thing hits the streets as well.

The two additions that allow you to perform such messaging, are window.postMessage and an eventlistener for events of the “message” type to handle the message. A pretty straightforward example of this can be found on JQuery’s John Resig’s site (see also his lastest blog entry about postMessage). As cross-domain javascript can be a potential big security risk, taking into account some precautions is really really really really really necessary. Really!

On the downside (as if security is not a problem); this brand new feature is only available in Firefox 3 for now. My own little test (a copy of John Resig’s example with some minor tweaks) worked in Opera 9.2x (and 9.5b) as well, but postMessage seems to have been dropped from the final Opera 9.5, as the tests on Opera Labs don’t seem to work any more either. Support for postMessage is also available in Webkit (Safari‘s backbone) nightly builds and in Microsoft’s IE 8 BETA (with the event being ‘onmessage’ instead of ‘message’ and some other quirks but hey, this is beta, no?).

So expect postMessage to be available in all major browsers by the end of the year. But why wait if you know that Facebook is already using postMessage in their chat application. I wonder what they fall back to if it is not available though …

Firefox 3rc1 shines in Javascript benchmark

blazing firefox3As the official release of Firefox 3 is getting closer, with Release Candidate 1 being available since May 17th, I decided to boldly go where codinghorror has gone before and do a quick-and-dirty Javascript-performance comparison of the different browsers I’ve got installed on my Dell Latitude D620 laptop, using Webkit’s Sunspider benchmark.

Let’s start with the results for the browsers on my Windows XP SP2 installation, ordered from slowest to fastest. Each test was executed 2 times, clicking on the results will teleport you to the detailed results where you can paste the URL’s of another test to compare.

The MSIE7-results are probably not entirely representative, as I use Tredosoft’s standalone IE7. This is a bit of a hack to have IE7 on my otherwise MSIE6-based system. Moreover my corporate Windows-installation is infested with crapware, notably McAfee OAS and Zonealarm seem to be slowing things down enormously. The codinghorror-tests indeed show significantly better results for this browser, although IE does have serious issues with string concatenation, which should be fixed in IE8.

On the same hardware, but booting in Ubuntu 8.04 (Linux) form my external USB HD (a.k.a. my ‘disktop‘), I got the following results:

Firefox 3 RC1 seems slightly slower then b5, but maybe the Ubuntu-b5-version is compiled with optimizations? Firefox is also faster on Ubuntu, but the anti-virus-bloat is probably messing with our heads here (although Opera is slower on Linux, go figure).

The general conclusion however; Firefox 3 is a huge step forward as far Javascript-performance is concerned. Users of javascript-heavy web-applications such as Gmail, Google Reader, Zoho Office and Zimbra should benefit enormously from this. It would however be very interesting to perform similar tests with regards to ‘normal page rendering’ (html/css). Does anyone know of such benchmarks?

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