function DateAdd(interval, number, date) {    switch (interval) {    case "y ": {        date.setFullYear(date.getFullYear() + number);        return date;        break;    }    case "q ": {        date.setMonth(date.getMonth() + number * 3);        return date;        break;    }    case "m ": {        date.setMonth(date.getMonth() + number);        return date;        break;    }    case "w ": {        date.setDate(date.getDate() + number * 7);        return date;        break;    }    case "d ": {        date.setDate(date.getDate() + number);        return date;        break;    }    case "h ": {        date.setHours(date.getHours() + number);        return date;        break;    }    case "mi ": {        date.setMinutes(date.getMinutes() + number);        return date;        break;    }    case "s ": {        date.setSeconds(date.getSeconds() + number);        return date;        break;    }    default: {        date.setDate(d.getDate() + number);        return date;        break;    }    }}var now = new Date();// 加五天.var newDate = DateAdd("d ", 5, now);alert(newDate.toLocaleDateString())// 加两个月.newDate = DateAdd("m ", 2, now);alert(newDate.toLocaleDateString())// 加一年newDate = DateAdd("y ", 1, now);alert(newDate.toLocaleDateString())

 

  （原文有重复的参数m，记得修改一下）