WordPress - Enqueue scripts for only if LT IE 9

Question

In a WordPress theme, how do you conditionally include scripts for ie8 and below? This is primarily to apply polyfills for various html5/css3 features. I see that wp has the $is

Answer 1

As wordpress is a PHP script, it can access server variable via $_SERVER

Then you can search for detect browser with PHP, PHP: If internet explorer 6, 7, 8 , or 9