javascript 当前日期加(天、周、月、年)

//create the date 
var myDate = new Date(); //add a day to the date 
myDate.setDate(myDate.getDate() + 1); 
//add a week 
myDate.setDate(myDate.getDate() + 7); 
//add a month 
myDate.setMonth(myDate.getMonth() + 1); 
//add a year 
myDate.setYear(myDate.getYear() + 1);