JavaScript自定义DateDiff函数(兼容所有浏览器)

<script type="text/javascript"> 
function NewDate(str) { 
str = str.split('-'); 
var date = new Date(); 
date.setUTCFullYear(str[0], str[1] - 1, str[2]); 
date.setUTCHours(0, 0, 0, 0); 
return date; 
} 
function TimeCom(dateValue) { 
var newCom; if (dateValue == "") { 
newCom = new Date(); 
} else { 
newCom = NewDate(dateValue); 
} 
this.year = newCom.getYear(); 
this.month = newCom.getMonth() + 1; 
this.day = newCom.getDate(); 
this.hour = newCom.getHours(); 
this.minute = newCom.getMinutes(); 
this.second = newCom.getSeconds(); 
this.msecond = newCom.getMilliseconds(); 
this.week = newCom.getDay(); 
} 
function DateDiff(interval, date1, date2) { 
var TimeCom1 = new TimeCom(date1); 
var TimeCom2 = new TimeCom(date2); 
var result; 
switch (String(interval).toLowerCase()) { 
case "y": 
case "year": 
result = TimeCom1.year - TimeCom2.year; 
break; 
case "m": 
case "month": 
result = (TimeCom1.year - TimeCom2.year) * 12 + (TimeCom1.month - TimeCom2.month); 
break; 
case "d": 
case "day": 
result = Math.round((Date.UTC(TimeCom1.year, TimeCom1.month - 1, TimeCom1.day) - Date.UTC(TimeCom2.year, TimeCom2.month - 1, TimeCom2.day)) / (1000 * 60 * 60 * 24)); 
break; 
case "h": 
case "hour": 
result = Math.round((Date.UTC(TimeCom1.year, TimeCom1.month - 1, TimeCom1.day, TimeCom1.hour) - Date.UTC(TimeCom2.year, TimeCom2.month - 1, TimeCom2.day, TimeCom2.hour)) / (1000 * 60 * 60)); 
break; 
case "min": 
case "minute": 
result = Math.round((Date.UTC(TimeCom1.year, TimeCom1.month - 1, TimeCom1.day, TimeCom1.hour, TimeCom1.minute) - Date.UTC(TimeCom2.year, TimeCom2.month - 1, TimeCom2.day, TimeCom2.hour, TimeCom2.minute)) / (1000 * 60)); 
break; 
case "s": 
case "second": 
result = Math.round((Date.UTC(TimeCom1.year, TimeCom1.month - 1, TimeCom1.day, TimeCom1.hour, TimeCom1.minute, TimeCom1.second) - Date.UTC(TimeCom2.year, TimeCom2.month - 1, TimeCom2.day, TimeCom2.hour, TimeCom2.minute, TimeCom2.second)) / 1000); 
break; 
case "ms": 
case "msecond": 
result = Date.UTC(TimeCom1.year, TimeCom1.month - 1, TimeCom1.day, TimeCom1.hour, TimeCom1.minute, TimeCom1.second, TimeCom1.msecond) - Date.UTC(TimeCom2.year, TimeCom2.month - 1, TimeCom2.day, TimeCom2.hour, TimeCom2.minute, TimeCom2.second, TimeCom1.msecond); 
break; 
case "w": 
case "week": 
result = Math.round((Date.UTC(TimeCom1.year, TimeCom1.month - 1, TimeCom1.day) - Date.UTC(TimeCom2.year, TimeCom2.month - 1, TimeCom2.day)) / (1000 * 60 * 60 * 24)) % 7; 
break; 
default: 
result = "invalid"; 
} 
return (result); 
} 
</script>