Question

My wish is to know how I can program a mobile website, that fit to all mobile phones.

Are there any special approaches to recognize a device and render the code according to it?

Which tools and coding languages are required?

My first thought was to hold the website in XML, which would be parsed depending on the device.

You have to consider old phones, even devices with only wap support.

For example: The mobile website has to recognize Nokia N75 and render/send the code that looks optimal for this device. Same thing with an iPhone or a Motorola Razr.

Answer 1

There are all sorts of problems associated with developing mobile websites. Doing it well takes a lot of time and effort, as phones have such varying support of web standards. There are tools that do it for you, such as the Mobile Web Toolkit and Vodafone’s PartnerMl. These tend to force you to write your pages using dedicated XML tags which describe a limited set of elements and styles that can be rendered on the page. The phone requests these xml pages, and the server side software intercepts the request, examines the type of phone (the User Agent), and serves back markup appropriate to that phone. The disadvantage of this system is that it is very inflexible; you are limited to the set of XML elements that the tool supplies, rather than the full flexibility of HTML.

If you want to do it yourself, essentially, you have to do the following.

1. Using server-side code, examine the User Agent in the Http Header. This tells you what kind of phone/browser made the request
2. Output appropriate markup and CSS for that user agent.

Useful tools are the User Agent Switcher add-in for Firefox. Using this, you can, for instance, visit the BBC’s website, pretending to be various devices. You will see that the BBC outputs 3 or 4 versions of its markup, as well as 3 or 4 different versions of the CSS, depending on the user agent.

mobiForge contains useful information. WURFL and DeviceAtlas are databases that allow you to determine the capabilities of the device that has made the request.

You will quickly realise that you will have to keep your design simple, and it’s best not to rely on Javascript, as only the most modern phones can handle it well.