How to Validate & Test Your Designs for the Mobile Web

Brian Suda

Following on from my last piece on user targeting for the mobile web, in this article we’ll look at validation and testing for mobile to ensure your site is just as compliant and bug-free on smartphones and tablets as it is on the desktop. Validation and testing may not be the most exciting areas in web design, but they’re just as important as learning how to make things look great.


Desktop browsers can be quite forgiving. A few misplaced HTML tags here and there will, more often than not, be fixed on the fly so that your page is rendered correctly. However, the “smarts” built into desktop browsers in order to perform this error handling equate to more code, which means a bigger install and more processing power.

Mobile browsers, on the other hand, are much less forgiving. A browser running on a mobile device generally won’t have the luxury of a 2 GHz processor and 100MB of disk space. Therefore, you must check, validate, and recheck your markup, time and time again.

Much of the checking and validation of a mobile web site can be done through a normal desktop browser. If you’re developing in XHTML, for example, you can reuse all of the same tools that you use to validate traditional sites:

You’ll notice at this point that we haven’t yet discussed checking to see if the mobile site works correctly on a mobile device. Once you’ve received the green light from several validators, you’ll need to get a few different types of phones to perform some actual tests.


Testing your site with a web browser on a desktop computer can only get you so far in terms of simulating the mobile experience. There are many elements of mobile device usage that can’t be replicated accurately in this way. For example, a mobile operator might restrict packet sizes to something smaller than you expected, and therefore won’t even send your web page or its images! Additionally, content mime types could be an issue between browsers — are you serving the pages with the correct text/html or application/xml+xhtml? What kind of image formats can the phone display?

Due to the small footprint in memory and on disk, mobile browsers are not as robust as desktop browsers, so the best advice is test, test, test! Granted, not everyone can afford to test on every phone that’s available on the market, but there are alternatives:

1. Emulators

There are plenty of online emulators and offline emulators that allow you to quickly see images in context and the general layout, but they’re not real devices, and therefore they have their own quirks and differences. These tools can act as a good first pass to find common issues. Also, they’re free to use, so there’s no reason to not have a peek in an emulator, but you can’t call a site viewed on an emulator “tested”.

2. Rent Time

Renting time is another option. There are services that allow you to upload or view the content one multiple phones in real time. You control the different phone’s features remotely. This service does cost money, but it’s still cheaper than purchasing lots of different phones. For a basic mobile web site, this service probably isn’t needed.

3. Buy a Handful of Phones

Buying a small subset or representative phones is a possibility. If you’re planning on doing more mobile development, spending a little money up front can really help. You probably need to purchase 5 or 6 phones representing the major brands and types.

You’ll need some sort of Windows smart phone — we test on an HTC Mogul PPS-6800 using Internet Explorer on Windows CE, which gives a representative coverage for all Windows Mobile devices. You’ll also need a Nokia model phone. We test on a Nokia 6600 running Symbian Series 6 OS and the built-in Services and optional Opera browsers. You’ll need a Sony Ericsson phone. The model we use is a T630, which covers Sony’s Internet Services. Lastly, you should test in whatever model is most popular in your audience. You do not need these exact phones, but these types of devices will allow you to quickly see the minor differences in the phone browsers and cover the majority of potential customers.

4. Ask Your Friends

Finally, you can simply ask your friends. We all know at east 5 or 6 co-workers or colleagues who would happily lend us their phone for a couple of minutes. Once you’ve tested your web site with the online emulators and validators, test it on the borrowed mobile phones. The pre-tests should have fixed all but the issues that are specific to each phone. Take notes, make corrections, and test again, and again — and again! — until you’re satisfied.

Depending on your budget, one of those options will suit you. Spending just a little time and money really can go a long way — especially if this is your first mobile web site. Getting your test suite right will allow you to find common issues, while helping you to build a library of working HTML, CSS, and JavaScript code that’s known to be tested and can be reused in future projects.

What resources and services have you used for mobile site validation and testing? Share them in the comments!