var modal = new DayPilot.Modal(); JavaScript runtime error: Object doesn't support this action

I am trying to display the modal using the code
function create(start, end, resource) {
var modal = DayPilot.Modal();
modal.closed = function () {
if (this.result == "OK") {
dps.commandCallBack("refresh");
}
dps.clearSelection();
}
modal.showUrl("New.aspx?start=" + start + "&end=" + end + "&resource=" + resource);
}
But I am getting this error 0x800a01bd - JavaScript runtime error: Object doesn't support this action