how to detect internet explorer and firefox using PHP?

Question

how to detect internet explorer and firefox using PHP?

Answer 1

you can use $_SERVER['HTTP_USER_AGENT'] as found in the php manual.

However, be aware that this can be changed by the user and some browsers even provide the ability to do this VERY easy (e.g. Konqueror). A lot of plugins are available to do the same.
Never ever trust this string.