alecto,
 
$('div.forabg').on('mouseenter mouseleave', '.trigger.inactive', function(event) {
    var time = 100, opacity = event.type == 'mouseenter' ?  '1.0' : (time = 0,'0.3');
    $(event.delegateTarget).stop(true,true).delay(time).animate({ opacity: opacity }, 300)
})