What is Cross-Browser Compatibility?

Cross-browser compatibility is something that all decent web designers have to offer as standard, but most non-techie people are baffled by, and don’t realise they need, let alone know whether their web designer is doing or not. So what does it mean, in theory and in practice?
Well, anecdotal evidence shows that an awful lot of people don’t know what the word ‘browser’ means, which obviously starts the confusion. For those of you that don't know, your browser is essentially the programme you use to view the Internet. Many people don’t realise they have a choice (which is probably why there is still such a high prevalence of IE6, and so many web designers tearing their hair out). Microsoft has the largest share of the market, with its Internet Explorer that happens to come with Windows.
Coming up second is Firefox, an open source browser from Mozilla. After those two are Safari (Apple’s offering), Opera and now Google have brought out their own browser, called Chrome. All browsers are free, and can be downloaded from the Internet (see below for links).

To add to the confusion, the makers of these browsers regularly improve and update them and bring out new versions, hence IE6, IE7, IE8 etc being earlier and later versions of Internet Explorer.
If you’re not sure and want to know what browser and version you are using, click on this useful link: http://www.findmebyip.com/.
So now you’re all in the know about browsers, I guess you want to know what the problem with cross-browser compatibility is.
Well, the problem is that the different web browsers interpret things in different ways. Websites are written in ‘languages’ and that’s a useful analogy. The Internet 'speaks' in a foreign language. Let’s call it Hutmel. IE, Firefox, chrome etc have all learned Hutmel, but at different schools, and so when they translate the Hutmel into a language you can understand – or see – they each tell you something slightly different.
Now, there are standards – an Internationally accepted Hutmel dictionary if you will – set out by W3C (the World Wide Web Consortium), but there is no legal obligation to abide by them.
So certain major browsers don’t. They take the attitude that they might be able to improve on what the web designer was doing in a ‘I think what they meant to say...’ kind of way. This is all very well as far as it goes, but falls down as soon as there are other browsers who don’t take liberties with the language, as the same phrase can end up having different interpretations – and as we all know, that’s how wars are started.
So cross-browser compatibility is where web designers must build some sections of each website multiple times in order for it to appear the same in the different browsers. Ignore one browser and the website will look broken to those users.
There are probably over a hundred browsers (source) so it would be impractical for web designers to make sure each website was compatible with every single one. So we tend to concentrate on the Big Five – IE, Firefox, Safari, Opera and Chrome.
One final thing - if your browser check showed up as IE6, you are using one of the least standards compliant browsers around – upgrade now for a faster, better experience and to save web designers’ hair!
If you’d like to see what sort of interpretations are possible, visit http://browsershots.org, enter a URL and see the results. If they all look the same, the website is cross browser compatible!