Some websites deliver a different version of the web page to different browsers (or different versions of the same browser). This is usually done at either at the web server level through scripts (programs) that run on the server itself, or on the web page level, through JavaScripts inserted into the web page. The practice is known as "browser sniffing".
Even if you do not know what browser sniffing is, this section may still apply to you. If
[Only Registered users can see links . Click Here To Register...] have inserted some sort of pop-up menu script that you obtained from a third-party website, your site may inadvertently contain browser-sniffing facilities. Some menu scripts incorporate browser sniffing to work around differences among the various browsers. Get an updated version of the third-party script that supports IE8 if your site uses such facilities. (Before you ask, don't worry if you're using the menu generated by the CSS Navigation Menu Bar Button Wizard. The menu generated is purely CSS based, and contains no browser sniffing.)
For those who have written their own scripts, you may need to update it to recognize IE 8. That is, you will need to add the IE8 user-agent string to your various tests.
If Compatibility View is enabled, IE uses the following string. Note that the "Windows NT 6.0" portion below is for Vista. The version number "6.0" will obviously be different if the visitor is using Windows XP ("5.1") or Windows 7 ("6.1").
In a nutshell, scan for "MSIE 8.0" if you need to identify IE running in standards view. If you just need to detect IE 8.0, whether it's running in standards mode or Compatibility View, search for the string "Trident/4.0".
Although IE8 is more standards-compliant than all its previous versions, its standards support is still not complete. For example, the "outset" and "inset" border styles mentioned in How to Create 3D Buttons Using CSS do not appear to be implemented in IE8 RC1. (Or at least, I can't seem to spot any difference in the borders using these styles and those using "solid" style.)
As a result, you probably should not just assume that the same style sheet that you use for Opera and Firefox will work identically for IE8. If your use of CSS is simple, or you don't mind a slightly degraded experience for your visitors in IE8, you can just ignore the differences (if any) and use one stylesheet for IE8 and the other browsers. Alternatively, if your styles are complicated, you may need to create yet another style sheet just for IE 8 that incorporate workarounds for the unsupported aspects of CSS 2, 2.1 and 3. Or use the lowest common denominator among the browsers.
03-06-2009, 06:35 PM
Browser Sniffing
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