When I attended Mobile World Congress in February one of my goals was to explore the merits of the various different approaches to writing cross-platform mobile apps. One of the key ones is PhoneGap, and I got in touch with Nitobi’s president and co-founder André Charland. As it turned out he was not at that particular event, but he kept in touch and I spoke to him last week.

PhoneGap works by using the installed HTML and JavaScript engine on the device as a runtime for apps. That is not as limiting as it may sound, since today’s devices have high performance JavaScript engines, and PhoneGap apps can be extended with native plug-ins if necessary. But aren’t there inconsistencies between all these different browser engines?

Sure, it’s kinda like doing web development today. Just a lot better because it’s just different flavours of WebKit, not WebKit, Gecko, whatever is in IE, and all sorts of other differentiation. So that’s definitely how it is, but that is being overcome rather quickly I’d say with modern mobile JavaScript libraries. There’s JQuery Mobile, there’s Sencha Touch, there’s DoJo Mobile just released, SproutCore, which is backed by Strobe, which is kinda the core of Apple’s MobileMe.

There’s tons of these things, Zepto.js which is from the scriptaculous guy, Jo which is a framework out of a Palm engineer, the list of JavaScript frameworks coming out is getting longer and longer and they’re getting refined and used quite a bit, and those really deal with these platform nuances.

At the same time, phone manufacturers, or iOS, Android, WebOS, and now RIM, they’re competing to have the best WebKit. That means you’re getting more HTML5 features implemented quicker, you’re getting better JavaScript performance, and PhoneGap developers get to take advantage of that.

says Charland. He goes further when I put to him the argument made by native code advocates – Apple CEO Steve Jobs among them – that PhoneGap apps can never achieve the level of integration, the level of performance that they get with native code. Will the gap narrow?

I think it will go away, and people will look back on what they’re saying today and think, that was a silly thing to say.

Today there are definitely performance benefits you can get with native code, and our answer to that is simply that PhoneGap is a bundle made of core libraries, so at any point in your application that you don’t want to use HTML and JavaScript you can write a native plugin, it’s a very flexible, extensible architecture … So you can do it. We don’t necessarily say that’s the best way to go. Really if you’re into good software development practices the web stack will get you 90%, 95% of the way there, so that apps are indistinguishable from native apps.

Some of the native features we see in iOS apps, they’re reminiscent of Flash home pages of ten years ago, sure you can’t do it in HTML and JavaScript but it doesn’t add any value to the end user, and it detracts from the actual purpose of the application.

The other thing is, a lot of these HTML and JavaScript things, are one step away from being as good in a web stack as they are in native. When hardware acceleration gets into WebKit and the browser, then performance is really just as good.

Charland is also enthusiastic about Adobe’s recent announcement, that PhoneGap is integrated into Dreamweaver 5.5:

Two things are exciting from our perspective. It gives us massive reach. Dreamweaver is a widely used product that ties in very nicely to the other parts of the creative suite toolchain, so you can get from a high-level graphic concept to code a lot quicker. Having PhoneGap and JQuery Mobile in there together is nice, JQuery Mobile is definitely one of the more popular frameworks that we see our community latching on to.

The other thing is that Dreamweaver targets a broader level of developer, it’s maybe not super hard core, either Vi or super-enterprise, Eclipse guys, you know, it’s people who are more focused on the UI side of things. Now it gives them access to quickly use PhoneGap and package their applications, test them, prove their concepts, send them out to the marketplace.

He says Adobe should embrace HTML and Flash equally.

I also asked about Windows Phone support, and given that Microsoft shows no sign of implementing WebKit, I was surprised to get a strongly positive response:

We have something like 80% of the APIs in PhoneGap running on Windows Phone already. That’s open and in the public repo. We are just waiting basically for the IE9 functionality to hit the phone. The sooner they get that out in public, the sooner we can support Windows Phone 7. We have customers knocking at our door begging for it, we’ve actually signed contracts to implement it, with some very large customers. Just can’t there soon enough, really. I think it’s an oversight on their part to not get IE9 onto the phone quicker.

PhoneGap is at version 0.94 at the moment; Charland says 0.95 will be out “in a few weeks” and he is hoping to get 1.0 completed by O’Reilly OSCON in July.

I’ve posted nearly the complete transcript of my interview, so if you are interested in Charland’s comments on building a business on open source, and how PhoneGap compares to Appcelerator’s Titanium, and what to do about different implementations of local SQL on devices, be sure to read the longer piece.