GZip encoding - what are the potential issues (old versions of IE etc)?

I can vaguely remember that there are certain older versions of certain browsers that do weird things with GZip encoding - in particular I seem to recall a bug in IE which resulted in JavaS开发者_JAVA技巧cript sent over GZip getting mangled.

Vague recollections aren't much practical use though. Does anyone know exactly what kind of issues there are and which user agents they affect?

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Which browsers can handle Content-Encoding: gzip

Some common htaccess rules for a starter

# Netscape 4.x has some problems...
BrowserMatch ^Mozilla/4 gzip-only-text/html

# Netscape 4.06-4.08 have some more problems
BrowserMatch ^Mozilla/4\.0[678] no-gzip

# MSIE masquerades as Netscape, but it is fine
BrowserMatch \bMSIE !no-gzip !gzip-only-text/html

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Basically there are two things you need to do:

1. Ensure the browser accepts GZip encoding. See Supercharging Javascript, Part 2: GZip Everything for a PHP example and
2. Handle buggy versions of IE when dealing with secure content. See Supercharging Javascript, Part 6: The Internet Explorer Problem.

Although these examples are in PHP the principles are universal. You don't say what language you're using.