Blog Archive for / testing /
Testing Your Website in Multiple Browsers
Monday, 03 December 2007
When designing websites, it is very important to check the results in multiple web browsers — something that looks fine in Internet Explorer may look disastrous in Firefox, and vice-versa. This problem is due to the different way in which each web browser interprets the HTML, XHTML and CSS standards, combined with any bugs that may be present. If you're designing a website, you have no control over which browser people will use to view it, so you need to ensure that your website displays acceptably in as many different browsers as possible.
The only way to know for sure how a website looks in a particular browser is to try it out. If you don't check it, how do you know you won't hit a bug or other display quirk? However, given the plethora of web browsers and operating systems out there, testing in all of them is just not practical, so you need to choose a subset. The question is: which subset?
Popular browsers
Thankfully, most people use one of a few "popular" browsers, but that's still quite a few. In my experience, on Windows, the most popular browsers are Firefox, Internet Explorer and Opera, on Linux most people use Firefox, Mozilla or Netscape and on MacOS most people use Safari or Camino. Obviously, the relative proportions of users using each browser will vary depending on your website, and target niche — a website focused on non-technical users is far more likely to find users with Internet Explorer on Windows than anything else, whereas a website focused on linux kernel development will probably find the popular browser is Firefox on linux.
Which version?
It's all very well having identified a few popular browsers to use for testing, but an equally crucial aspect is which version of the browser to test. Users of Firefox, Opera, Mozilla, and recent versions of Netscape might be expected to upgrade frequently, whereas users of Internet Explorer might be far less likely to upgrade, especially if they are non technical (in which case they'll stick with the version that came with their PC). Checking the logs of some the websites I maintain shows that the vast majority of Firefox users (90+%) are using some variant of Firefox 2.0 (though there are a smattering all the way back to Firefox 0.5), whereas Internet Explorer users are divided between IE7 and IE6, with the ratio varying with the site.
Don't forget a text-only browser
A text only browser such as Lynx is ideal for seeing how your site will look to a search engine spider. Not only that, but certain screen reader applications will also give the same view to their users. Consequently, it's always worth checking with a text-only browser to ensure that your site is still usable without all the pretty visuals.
Multiple Browsers on the same machine
Having chosen your browsers and versions, the simplest way to test your sites is to install all the browsers on the same machine. That way, you can just open the windows side by side, and compare the results. Of course, you can't do this if the browsers run on different platforms, but one option there is to use virtual machines to test on multiple platforms with a single physical machine. Testing multiple versions of Internet Explorer can also be difficult, but TredoSoft have a nice little package called Multiple IEs which enables you to install multiple versions of Internet Explorer on the same PC. Thanks to Multiple IEs, on my Windows XP machine I've got IE3, IE4.01, IE5.01, IE5.5, IE6 and IE7, as well as Firefox, Opera, Safari and Lynx!
Snapshot services
If you don't fancy installing lots of browsers yourself, or you don't have access to the desired target platform, you can always use one of the online snapshot services such as browsershots (free) or browsercam (paid). These provide you with the ability to take a snapshot of your website, as seen in a long list of browsers on a long list of platforms. Browsercam also provides remote access to the testing machines, so you can interact with your sites and check dynamic aspects, such as Javascript — something that's becoming increasingly more important as AJAX becomes more prevalent.
Posted by Anthony Williams
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Tags: testing, browsers, website, webdesign
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Testing on Multiple Platforms with VMWare
Tuesday, 27 November 2007
Whilst testing on multiple platforms is important, it can be difficult to obtain access to machines running all the platforms that you wish to test on. This is where virtualization software such as VMWare comes in handy: you don't need to have a separate machine for each tested platform — you don't even need a separate partition. Instead, you set up a Virtual Machine running the target platform, which runs on top of your existing OS. This Virtual Machine is completely self-contained, running off a virtual hard disk contained in a file on your real disk, and with a virtual screen which can be shown in a window on your host desktop.
Virtual Networks
This can be incredibly useful: not only can you test on multiple platforms without repartitioning your hard disk, but you can have multiple virtual machines running simultaneously. If you're developing an application that needs to run on multiple platforms, this can be invaluable, as you can see what the application looks like on different operating systems simultaneously. It also allows you to test network communication — each virtual machine is entirely independent of the others, so you can run a server application on one and a client application on another without having to build a physical network.
Get Started with a Pre-built Virtual Machine
VMWare have a repository of pre-built virtual machines, that they call "appliances". This makes it very easy to get started, without all the hassle of installing the OS. Some appliances even come with pre-installed applications — if you want to try a Ruby on Rails app on linux, then the UbuntuWebServer appliance might be a good place to start.
Warning: Virtual Machines use Real Resources
It's worth noting that the resource use (CPU, memory, disk space) is real, even if the machines are virtual — if you run a CPU-intensive application on your virtual machine, your system will slow down; if you give 3 virtual machines 1Gb of memory each but you only have 2Gb installed, you're going to see a lot of swapping. Virtual machines are not full-time replacements for physical ones unless you have a server with a lot of resources. That said, if you do have a server with a lot of resources, running separate systems and applications in separate virtual machines can make a lot of sense: the individual systems are completely isolated from one-another, so if one application crashes or destroys its (virtual) disk, the others are unaffected. Some web hosting companies use this facility to provide each customer with root access to their own virtual machine, for example.
It's also worth noting that if you install a non-free operating system such as Microsoft Windows, you still need a valid license.
Alternatives
VMWare Server is currently a free download for Windows and Linux, but it's not the only product out there. VirtualBox is also free, and runs on Windows, Linux and MacOSX. One nice feature that VirtualBox has is "seamless Windows": when running Microsoft Windows as the guest operating system, you can suppress the desktop background, so that the application windows from the virtual machine appear on the host desktop.
Another alternative is QEMU which offers full-blown emulation as well as virtualization. This allows you to experiment with operating systems running on a different CPU, though the emulated hardware can be quite limited.
Posted by Anthony Williams
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Tags: testing, vmware, virtualization, virtual machine
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