$(document).ready(function() {
$(window).bind('mousewheel DOMMouseScroll MozMousePixelScroll', function(event) {
delta = parseInt(event.originalEvent.wheelDelta || -event.originalEvent.detail);
if (delta >= 0) {
$('#content').html('Вверх');
} else {
$('#content').html('Вниз');
}
});
})