Calculo con fecha de jscalendar

[juanito1712]

http://www.dynarch.com/jscal/

Calendar.setup({
cont : "calendar-container",
weekNumbers : true,
selectionType : Calendar.SEL_MULTIPLE,
selection : Calendar.dateToInt(new Date()),
showTime : 12,
onSelect : function() {
var count = this.selection.countDays();
if (count == 1) {
var date = this.selection.get()[0];
date = Calendar.intToDate(date);
date = Calendar.printDate(date, "%A, %B %d, %Y");
$("calendar-info").innerHTML = date;
} else {
$("calendar-info").innerHTML = Calendar.formatString(
"${count:no date|one date|two dates|# dates} selected",
{ count: count }
);
}
},
onTimeChange : function(cal) {
var h = cal.getHours(), m = cal.getMinutes();
// zero-pad them
if (h < 10) h = "0" + h;
if (m < 10) m = "0" + m;
$("calendar-info").innerHTML = Calendar.formatString("Time changed to ${hh}:${mm}", {
hh: h,
mm: m
});
}
});

quizá puedas jugar con onselect