[Tfug] Opera, Firefox, IE, etc.

[Glen Pfeiffer]

On 04/07/2007 09:09 AM, christopher floess wrote:
> Do any of you know what it is that's different between Opera
> and Firefox and IE that makes the websites that say "This
> website is best viewed with Internet Explorer or Firefox"
> display stuff badly in Opera, or not even functional at all
> under opera?

It is called User Agent Sniffing. All modern browsers send a
useragent string in the request header to the server. The site
creator may use this string to determine what browser you have so
they can tailor the dynamic behaviors to your browser. They do
this because the browsers all implement JavaScript differently. I
recommend the Wikipedia article, it is a pretty good read.
http://en.wikipedia.org/wiki/User_agent

It is frowned upon by pretty much everybody that does not use IE
on Windows. The preferred way to handle browser differences with
JavaScript is to test whether the browser implements the
functions you want to use. If not, then you use a different
function.

The following information I include not because I advocate it,
but because you have a right to know. Browsers like Firefox and
Opera allow you to change how the browser identifies itself to
the website via the useragent string. In Firefox you do this by
entering "about:config" in the url bar and finding one of the
"useragent" strings. You can also install an extension that does
it for you, User Agent Switcher is one. Opera also allows you to
change it in the settings. I think it is called "Browser
Identification" or something to that effect.

If you absolutely *must* use a site that does this then by all
means, change the settings so you can access it. But please,
change it back when you are done on that site. If you do not,
then the logs of the sites you visit will incorrectly report what
browser you use and affirm their decision to do user agent
sniffing. If they see Firefox, Opera, Epiphany, Iceweasel,
Konquerer, etc enough, they may begin to realize that they should
change.

I recommend that you email the businesses that do this and do
business with a site that does not exclude these browsers.

-- 
Glen