jsは2つの時間の間の日数差を計算する実例的なコードです.

 
  
//        
  
function isLeapYear(year){ 
  
if(year % 4 == 0 && ((year % 100 != 0) || (year % 400 == 0))) 
  
{ 
  
     return true; 
  
} 
  
return false; 
  
} 
  
//         
  
function validatePeriod(fyear,fmonth,fday,byear,bmonth,bday){ 
  
if(fyear < byear){ 
  
return true; 
  
}else if(fyear == byear){ 
  
if(fmonth < bmonth){ 
  
   return true; 
  
} else if (fmonth == bmonth){ 
  
   if(fday <= bday){ 
  
    return true; 
  
   }else { 
  
    return false; 
  
   } 
  
} else { 
  
   return false; 
  
} 
  
}else { 
  
return false; 
  
} 
  
} 
  
//          
  
function dateDiff(d1,d2){ 
  
    var disNum=compareDate(d1,d2); 
  
    return disNum; 
  
} 
  
function compareDate(date1,date2) 
  
{ 
  
    var regexp=/^(\d{1,4})[-|\.]{1}(\d{1,2})[-|\.]{1}(\d{1,2})$/; 
  
    var monthDays=[0,3,0,1,0,1,0,0,1,0,0,1]; 
  
    regexp.test(date1); 
  
    var date1Year=RegExp.$1; 
  
    var date1Month=RegExp.$2; 
  
    var date1Day=RegExp.$3; 
   
  
    regexp.test(date2);
    var date2Year=RegExp.$1;
    var date2Month=RegExp.$2;
    var date2Day=RegExp.$3;
 
  
if(validatePeriod(date1Year,date1Month,date1Day,date2Year,date2Month,date2Day)){
firstDate=new Date(date1Year,date1Month,date1Day);
     secondDate=new Date(date2Year,date2Month,date2Day);
 
  
     result=Math.floor((secondDate.getTime()-firstDate.getTime())/(1000*3600*24));
     for(j=date1Year;j<=date2Year;j++){
  if(isLeapYear(j)){
      monthDays[1]=2;
  }else{
      monthDays[1]=3;
  }
  for(i=date1Month-1;i      result=result-monthDays[i];
  }
     }
     return result;
}else{
    alert('                 ，  ！');
    exit;
}
}