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Making iPad app work cross-browser

As someone who is timezone-maths challenged and forever dialling into international conference calls an hour early or an hour late, I greatly appreciated the intuitiveness of the everytimezone iPad app by Amy Hoy (idea & design) and Thomas Fuchs (development).

The accompanying blog post Making an iPad HTML5 App & making it really fast said “desktop browsers work, too!” but it didn’t work in Opera.

David Storey, Patrick Lauke and I set about exploring why. The answer was simple: browser-sniffing. The app was only looking for browsers with the strings “webkit” or “Gecko” in the user agent string, and only feeding those browsers the necessary code. So we copied the code and, as a proof of concept, added “opera” to the list of strings being sniffed, and made trivial amends to the JavaScript to send -o- prefixed styles.

Additionally, the main CSS was only using -webkit-border-radius and -moz-border-radius, while Opera and IE9 use the naked property name border-radius. (See my Writing cross-browser, future-proof CSS 3 for more on this.)

Adding this to our proof of concept made the application work in Opera. There are differences; Opera doesn’t support CSS Gradients so those don’t show (although an SVG gradient as a CSS background-image would work perfectly well) and a bug means it doesn’t pick up the Futura font. But visual differences are to be expected on the Web; it’s the content that’s king (or, in the case of an application, the functionality).

We sent this to Thomas, and very sportingly he made the code live, so now works in Opera too. The moral is that it’s pretty easy to make your sites work across all modern browsers and, while you might expect the user to be coming from one specific device, if your app is on the Web (rather than a W3C Widget or some proprietary format like Apple app store) you can expect visitors using other devices, browsers and operating systems.

Of course, it won’t work in IE9, even though it was announced yesterday that IE9 will support canvas, as the browser-sniffing locks out all versions of IE, past and future. That’s the downside to browser-sniffing: it’s completely non-futureproof. If you make a deliberate policy to block a browser, and a future version of that browser is capable of supporting your code, you have to go back and amend your blocking code. If you have hundreds of sites in your portfolio, that’s a massive commitment.

So congratulations s to Thomas and Amy for a lovely little app; I can now dial into conference calls with confidence and punctuality!

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One Response to “ Making iPad app work cross-browser ”

Comment by patrick h. lauke

“Of course, it won’t work in IE9, even though it was announced yersterday that IE9 will support canvas, as the browser-sniffing locks out all versions of IE, past and future.”

of course, changing from browser sniffing to feature detection here would solve the issue…we’ll leave that one for thomas to play with 🙂

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