JavaScript版DateAdd和DateDiff函数

function DateAdd(interval,number,date){
	switch(interval.toLowerCase()){
		case "y": return new Date(date.setFullYear(date.getFullYear()+number));
		case "m": return new Date(date.setMonth(date.getMonth()+number));
		case "d": return new Date(date.setDate(date.getDate()+number));
		case "w": return new Date(date.setDate(date.getDate()+7*number));
		case "h": return new Date(date.setHours(date.getHours()+number));
		case "n": return new Date(date.setMinutes(date.getMinutes()+number));
		case "s": return new Date(date.setSeconds(date.getSeconds()+number));
		case "l": return new Date(date.setMilliseconds(date.getMilliseconds()+number));
	} 
}

function DateDiff(interval,date1,date2){
	var long = date2.getTime() - date1.getTime(); //相差毫秒
	switch(interval.toLowerCase()){
		case "y": return parseInt(date2.getFullYear() - date1.getFullYear());
		case "m": return parseInt((date2.getFullYear() - date1.getFullYear())*12 + (date2.getMonth()-date1.getMonth()));
		case "d": return parseInt(long/1000/60/60/24);
		case "w": return parseInt(long/1000/60/60/24/7);
		case "h": return parseInt(long/1000/60/60);
		case "n": return parseInt(long/1000/60);
		case "s": return parseInt(long/1000);
		case "l": return parseInt(long);
	}
}