When Lotte Card, one of South Korea’s biggest credit card companies, wanted to create an augmented-reality app earlier this year, it faced a familiar conundrum: whether to develop a sophisticated custom app for each major mobile platform out there or produce a single less-capable Web app that works on any device via its browser. In the end, the company decided to do a bit of both.

With the help of mobile application platform Worklight, Lotte’s programmers created hundreds of HTML-based pages using standard tools—HTML5, CSS, and JavaScript—and then wrapped them up in native iOS and Android code so that the resulting bundle could be delivered, just like any other app, via the Apple and Android app stores.

The key advantage of Web apps over native mobile apps is cross-platform compatibility. They run in the standards-compliant browsers that are available on Android, Apple, BlackBerry, and Windows mobile devices, so (in theory at least) they have to be built only once. The disadvantages are that they lack access to such features of a device as the camera and the address book, they can’t use some of user-interface elements that are native to each platform, and they can’t be downloaded from Apple’s App Store or the Android Market.

Most native apps can tap into the device’s browser, in order to grab content from the Web. As the variety of mobile platforms grows, more companies may be drawn to using this capability, creating hybrid apps that use Web technologies but can be distributed via the usual app stores.

“The slickness of the user interface a developer can achieve in the native [app] model just isn’t worth the extra spending compared to the very nice level of user-interface experience they get from the hybrid option,” says Ron Perry, CTO of Worklight. Worklight uses the open-source PhoneGap platform to help developers package Web apps within native apps so that they can be downloaded from app stores.

The primary competitor to PhoneGap is Appcelerator’s Titanium Studio, a development environment that takes a slightly different approach. Instead of showing Web content within an app, this platform recompiles a Web app’s (JavaScript) code into native code that can access all the device-specific user-interface elements of iOS, Android, and BlackBerry’s platform. (It is not yet compatible with Windows Phone.)

The Titanium platform’s application-programming interface includes more than 1,000 elements that translate to native user-interface elements in the mobile operating systems Titanium supports. This allows Web developers to create products that are often indistinguishable from native apps.

The developers of Hotel Tonight, currently the number-one app in the travel section of the App Store, used the Titanium platform to create a location-specific app that helps travelers find nearby hotel rooms at discount rates.

And an app developed for the “Late Night with Jimmy Fallon” show, says Scott Schwarzhoff, vice president of marketing at Appcelerator, was deployed across both Android and iOS devices with “90 percent code reuse.”

One thing holding pure Web apps back is limited support for HTML5, the latest Web standard, which can be used to create a rich, native-app-like experience in some browsers.

“Each browser supports its own subset of HTML5 when you are talking about animation or graphical transitions,” says Yaniv Yaakubovich, a senior product manager at PayPal. He says this fragmentation is “a pretty big barrier,” to making Web apps function more like native ones across different devices.

Brian Kennish, formerly an engineer at Google who has argued that Web apps are the future of mobile development, believes hybrid apps could be an important step forward.

“Maybe the mobile operating systems [will] improve their somewhat clunky facilities for creating hybrid apps by wrapping a Web interface in native code,” says Kennish. Doing so would make it easier for apps developed using Web technologies to access the various features of a device.

Some apps such as high-end games that push the limits of a phone’s 3-D capabilities may never be deployed as Web or hybrid apps. But Ron Perry of Worklight believes that as mobile Web browsers become more compatible and standards-compliant, there will be less need for native apps.