How can I determine which version of IE a user is running in JavaScript?

Question

In some existing code there is a test to see if the user is running IE, by checking if the object Browser.Engine.trident is defined and returns true.

But how can I deter

Answer 1

If you really want to be sure you are using IE and a specific version then you could obviously use IE's conditional tags to only run certain code within IE. It's not really that pretty but at least you can be sure that it is really IE and not some spoofed version.

It's pretty self explanatory. In IE6 isIE is true and version is 6, In IE7 isIE is true and version is 7 otherwise isIE is false and version is -1

Alternatively you could just roll your own solution using code plagarised from jQuery.

var userAgent = navigator.userAgent.toLowerCase();
var version = (userAgent.match( /.+(?:rv|it|ra|ie)[\/: ]([\d.]+)/ ) || [])[1],
var isIE = /msie/.test( userAgent ) && !/opera/.test( userAgent ),