javascript判断日期是否合法

function IsDate(str) {     arr = str.split("-");     if(arr.length == 3)     {         intYear = parseInt(arr[0],10);         intMonth = parseInt(arr[1],10);         intDay = parseInt(arr[2],10);         if(isNaN(intYear) || isNaN(intMonth) || isNaN(intDay))         {             return false;         }         if(intYear > 2100 || intYear < 1900 || intMonth > 12 || intMonth < 0 || intDay > 31 || intDay < 0)         {             return false;         }         if((intMonth == 4 || intMonth == 6 || intMonth == 9 || intMonth == 11) && intDay > 30)         {             return false;         }         if(intYear % 100 == 0 && intYear % 400 || intYear % 100 && intYear % 4 == 0)         {             if(intDay > 29)                 return false;         }         else         {             if(intDay > 28)                 return false;         }         return true;     }     return false; }