Execute certain javascript if browser lt ie9

Execute certain javascript if browser lt ie9

I want to execute a certain code in jQuery if the browser is lower than
IE9. And yes, i already know about
<!--[if ... IE ]> <![endif]-->
But what i want is to check this condition within the scipt tag and with
jQuery document.ready
<script>
$(document).ready(function(){
//code to check if lt ie9
});
</script>
And this is not helping
<script>
$(document).ready(function(){
<!--[if ... IE ]>
//code to check if lt ie9
<![endif]-->
});
</script>
Please help