Detect IE version (prior to v9) in JavaScript

Question

I want to bounce users of our web site to an error page if they\'re using a version of Internet Explorer prior to v9. It\'s just not worth our time and money to

Answer 1

To reliably filter IE8 and older, checking global objects can be used:

if (document.all && !document.addEventListener) {
    alert('IE8 or lower');
}