码：
var date = new Date('2011', '01', '02');alert('the original date is ' + date);var newdate = new Date(date);newdate.setDate(newdate.getDate() - 7); // minus the datevar nd = new Date(newdate);alert('the new date is ' + nd);使用Datepicker：
$("#in").datepicker({ minDate: 0, onSelect: function(dateText, inst) { var actualDate = new Date(dateText); var newDate = new Date(actualDate.getFullYear(), actualDate.getMonth(), actualDate.getDate()+1); $('#out').datepicker('option', 'minDate', newDate ); }});$("#out").datepicker();可能会派上用场的其他东西：
getDate() Returns the day of the month (from 1-31)getDay() Returns the day of the week (from 0-6)getFullYear() Returns the year (four digits)getHours() Returns the hour (from 0-23)getMilliseconds() Returns the milliseconds (from 0-999)getMinutes() Returns the minutes (from 0-59)getMonth() Returns the month (from 0-11)getSeconds() Returns the seconds (from 0-59)
