Check with js is a media query fired src: http://bricss.net/post/22198838298/easily-checking-in-javascript-if-a-css-media-query-has

check-mq.html

<style>
@media (min-width: 45em) {
    body:after {
        content: 'widescreen';
        display: none;
        }
    }
</style>

<script>
var size = window.getComputedStyle(document.body,':after').getPropertyValue('content');
if (size == 'widescreen') {
    // go nuts
}
</script>