Writing compatibility code for older versions of non-IE browsers [closed]

Question

I was wondering if professional HTML/CSS/JS developers worry about compatibility with not the latest Firefox, Chrome or Opera? My experience with the browsers is that they just update automatically and there isn't REALLY a version system like for IE where you get major releases tied to new OS versions.

So do people worry about their code being compatible with an older Firefox version or do people just assume that if somebody's using their site that means they're connected to the internet thus they have the newest version of their non-IE browser if they choose to use one?

Answer 1

I would recommend you take a visit to http://caniuse.com/.

This site has very thorough browser support tables for versions of all common browsers, going back a pretty long way (certainly as far as anyone needs to worry about).

So that's the first thing CanIUse.com will do for you: It'll tell you for every major browser feature, what versions of which browsers support that feature. This can help you decide whether or not to use that feature in your site.

Secondly, they also have up-to-date browser usage statistics. This tells you for every version of every browser, what percentage of web users are using that particular browser/version. This can help you decide which browser versions to support. For example, if IE6 has 1% of the browser market, you may decide that's a small enough number of users to make the extra hassle of supporting it not worth the effort. The same will apply for other browsers.

More generally, of the major non IE browsers:

• Chrome has always has auto-update feature. Virtually everyone will be on the latest version, or at worst one version behind. Anyone using a version more than a couple of months old is an abberation.
• Firefox is now in the same position as Chrome for up-to-date users. However they also have a long-term support version (currently FFv10), which is not updated as often. You need to support this. In addition, users with version prior to their auto-update feature may not have upgraded. There are still a small but significant number of FF3.6 and FF4 users out there. Most other versions have pretty much faded away due to upgrades by now though.
• Opera is also pretty good at keeping itself up-to-date, and it seems that most Opera users are themselves quite mindful of this too, so you generally don't need to worry about old versions of Opera.
• Safari is the one where you might have to keep an eye on old versions. Safari has the problem that newer versions do not always support older hardware or operating systems, and therefore users with say a slightly out-of-date Macbook find that they can't upgrade to the latest Safari. There are therefore quite a number of versions of Safari still kicking around out there. But check the CanIUse stats for a clearer breakdown of the versions.