var old_width = parseInt(event.data.overlay.css('width'));
var delta = event.pageX + event.data.hotspot_x - old_width;
event.data.overlay.css({'width': old_width + delta});
var old_width = parseInt(event.data.overlay.css('width'));
var delta = event.pageX + event.data.hotspot_x - old_width;
event.data.overlay.css({'width': old_width + delta});