Fecha de verificación JS
Object.prototype.toString.call(date) === '[object Date]'
Miro Slav
Object.prototype.toString.call(date) === '[object Date]'
var stringval = '01/03/2012';
var testdate;
try {
testdate = $.datepicker.parseDate('mm/dd/yy', stringval);
// Notice 'yy' indicates a 4-digit year value
} catch (e)
{
alert(stringval + ' is not valid. Format must be MM/DD/YYYY ' +
'and the date value must be valid for the calendar.';
}