Something I ran into just now was returning an anchor's attribute consistently across browsers. So I have an anchor with an address like '/users/delete/5/' which does what you'd think it does. But I ran into an inconsistent return response in (you guessed it) ie6. In all fairness, it might not be IE6's fault, but it speaks more to a problem with mootools. While it is a nearly perfect library/framework, this does bug me.
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There are many browsers out there: IE6, IE7, IE8, FF, Opera, Safari, Chrome.
Then there are tons of mods for each of those. On the mac, a few lesser options (FF, Opera, Safari, soon to be Chrome). I used to scoff at Safari users when it was around the 2.0 release (even 3.0 seemed crap to me). When I adopted the Mac, however, Safari fell into a different light for me. The number one reason it did was because of it's speed.
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