Developing Portable Mobile Web Applications

What if you could write iPhone and iPad applications on Linux? And, what if those applications also ran on Android phones? Well, you can, by writing your application as a portable mobile Web application. Take advantage of HTML5 and JavaScript libraries to write rich Web applications that users can't tell from native applications. You even can have them install from iTunes and Android Market. Plus,
Packaging the App for Distribution

If you want to package a Web application for distribution on iTunes or Android Market, one way is to use the appropriate SDK and write a small wrapper application. The application creates a browser Intent (Android) or a UIWebView (iPhone) and gives it the location of index.html. We don't have room to go into the SDKs here, but the applications are literally a few lines of code.

Or, for iTunes, you can let a package like PhoneGap do the work for you. You still need the iPhone SDK, so you have to create the package on a Mac, but PhoneGap makes the process simpler. Once it's created, you can upload it to iTunes like any other iPhone app.

If you don't care about iTunes or Android Market, there's another way—package your application as an HTML5 Offline Application. Listing 3 is a manifest file, webnotes.manifest, that you put in the home directory of your application. You also need to add an attribute to the <html> element in index.html:


One more thing—if you're serving the files from an Apache Web server, the .htaccess file in your Web directory needs a line like:

AddType text/cache-manifest .manifest

This tells Apache to serve .manifest files with the correct MIME type. When a user first goes to the Web site, the server will download the files listed in the manifest and keep them on the device. On subsequent visits, the file will be reloaded if the manifest changes—even if the change is in a comment field.

On Apple devices, when users go to your Web site, they can touch + at the bottom of the browser to put an icon for that URL on their homescreen (remember that .icon attribute when we initialized jQTouch?). If you've created an off-line application, it loads and executes from local storage, much like a native application.


We defined Webnotes to be similar to an example application that comes with the Android SDK called NotePad. See Table 1 for a comparison of lines of code.

Table 1. Comparing Lines of Code

JavaScript 121
Source Lines722183

If the effort to write a line of code is about the same in any language, it would take about a fourth of the time to write the application as a Web application—and it runs on most mobile WebKit-based browsers. That's worth considering as you plan your next mobile application development.

Rick Rogers has been a professional embedded software developer for more than 30 years (FORTRAN to JavaScript). He's currently a Mobile Solutions Architect at Wind River Systems. He welcomes feedback on this article at


Rick Rogers has been a professional embedded developer for more than 30 years. Now specializing in mobile application software, when Rick isn't writing software for a living, he's writing books and magazine articles like this one.


Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Android compatibility.

tuna's picture

I'm getting my feet wet with mobile development and am trying to get this working. I'm developing on an HTC Droid Eris with Android 2.1. All I'm getting is a black screen. Any one have any ideas if it should work? Or where I should be looking?

"well documented elsewhere"

Anonymous's picture

"Installation of the tools is well documented elsewhere. The Resources section for this article gives pointers to the download URLs."

The resources indeed gives the pointers to the download URLs.
Is there also a link available for "well documented elsewhere"?
Is there also a pointer to the installation of the tools?

M. Moon

One Click, Universal Protection: Implementing Centralized Security Policies on Linux Systems

As Linux continues to play an ever increasing role in corporate data centers and institutions, ensuring the integrity and protection of these systems must be a priority. With 60% of the world's websites and an increasing share of organization's mission-critical workloads running on Linux, failing to stop malware and other advanced threats on Linux can increasingly impact an organization's reputation and bottom line.

Learn More

Sponsored by Bit9

Linux Backup and Recovery Webinar

Most companies incorporate backup procedures for critical data, which can be restored quickly if a loss occurs. However, fewer companies are prepared for catastrophic system failures, in which they lose all data, the entire operating system, applications, settings, patches and more, reducing their system(s) to “bare metal.” After all, before data can be restored to a system, there must be a system to restore it to.

In this one hour webinar, learn how to enhance your existing backup strategies for better disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible bare-metal recovery solution for UNIX and Linux systems.

Learn More

Sponsored by Storix