JavaScript版的DateAdd、DateDiff、IsDate函数

写了个JavaScript版的DateAdd、DateDiff、IsDate函数，大家评评!

需要说明的是，JavaScript中IsDate的参数必须为字符串，且支持6种不同的格式"yyyy-mm-dd || yyyy/mm/dd || dd-mm-yyyy || dd/mm/yyyy || mm-dd-yyyy || mm/dd/yyyy"，之所以不能使用日期作为参数是因为JavaScript根本没有不正确的日期，比如 new Date(2008,01,30)，构造函数会自动将它转换成正确的日期2008-03-01。


1.DateAdd函数：

<script language="javascript">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)); } }alert(DateAdd("s",1,new Date()));</script>

2.DateDiff函数：

<script language="javascript">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); }}alert(DateDiff("d",new Date(2008,03,01),new Date(2008,03,20)));</script>

3.IsDate函数：

<script language="javascript">function IsDate(dateval){ var arr = new Array(); if(dateval.indexOf("-") != -1){  arr = dateval.toString().split("-"); }else if(dateval.indexOf("/") != -1){  arr = dateval.toString().split("/"); }else{  return false; } //yyyy-mm-dd || yyyy/mm/dd if(arr[0].length==4){  var date = new Date(arr[0],arr[1]-1,arr[2]);  if(date.getFullYear()==arr[0] && date.getMonth()==arr[1]-1 && date.getDate()==arr[2]){   return true;  } } //dd-mm-yyyy || dd/mm/yyyy if(arr[2].length==4){  var date = new Date(arr[2],arr[1]-1,arr[0]);  if(date.getFullYear()==arr[2] && date.getMonth()==arr[1]-1 && date.getDate()==arr[0]){   return true;  } } //mm-dd-yyyy || mm/dd/yyyy if(arr[2].length==4){  var date = new Date(arr[2],arr[0]-1,arr[1]);  if(date.getFullYear()==arr[2] && date.getMonth()==arr[0]-1 && date.getDate()==arr[1]){   return true;  } } return false;}alert(IsDate("2008-02-28"));alert(IsDate("02/30/2008"));</script>