function HS_DateAdd(interval,number,date){
number = parseInt(number);
if (typeof(date)=="string"){var date = new Date(date.split("-")[0],date.split("-")[1],date.split("-")[2])}
if (typeof(date)=="object"){var date = date}
switch(interval){
case "y":return new Date(date.getFullYear()+number,date.getMonth(),date.getDate()); break;
case "m":return new Date(date.getFullYear(),date.getMonth()+number,checkDate(date.getFullYear(),date.getMonth()+number,date.getDate())); break;
case "d":return new Date(date.getFullYear(),date.getMonth(),date.getDate()+number); break;
case "w":return new Date(date.getFullYear(),date.getMonth(),7*number+date.getDate()); break;
}
}
function checkDate(year,month,date){
var enddate = ["31","28","31","30","31","30","31","31","30","31","30","31"];
var returnDate = "";
if (year%4==0){enddate[1]="29"}
if (date>enddate[month]){returnDate = enddate[month]}else{returnDate = date}
return returnDate;
}
function WeekDay(date){
var theDate;
if (typeof(date)=="string"){theDate = new Date(date.split("-")[0],date.split("-")[1],date.split("-")[2]);}
if (typeof(date)=="object"){theDate = date}
return theDate.getDay();
}
function HS_calender(){
var lis = "";
var style = "";
var now;
if (typeof(arguments[0])=="string"){
  selectDate = arguments[0].split("-");
  var year = selectDate[0];
  var month = parseInt(selectDate[1])-1+"";
  var date = selectDate[2];
  now = new Date(year,month,date);
}else if (typeof(arguments[0])=="object"){
  now = arguments[0];
}
var lastMonthEndDate = HS_DateAdd("d","-1",now.getFullYear()+"-"+now.getMonth()+"-01").getDate();
var lastMonthDate = WeekDay(now.getFullYear()+"-"+now.getMonth()+"-01");
var thisMonthLastDate = HS_DateAdd("d","-1",now.getFullYear()+"-"+(parseInt(now.getMonth())+1).toString()+"-01");
var thisMonthEndDate = thisMonthLastDate.getDate();
var thisMonthEndDay = thisMonthLastDate.getDay();
var todayObj = new Date();
today = todayObj.getFullYear()+"-"+todayObj.getMonth()+"-"+todayObj.getDate();

for (i=0; i<lastMonthDate; i++){  // Last Month's Date
  lis = "<li class='lastMonthDate'>"+lastMonthEndDate+"</li>" + lis;
  lastMonthEndDate--;
}
for (i=1; i<=thisMonthEndDate; i++){ // Current Month's Date
  if(today == now.getFullYear()+"-"+now.getMonth()+"-"+i){
   var todayString = now.getFullYear()+"-"+(parseInt(now.getMonth())+1).toString()+"-"+i;
   lis += "<li><a href=javascript:void(0) class='today' onclick='_selectThisDay(this)' title='"+now.getFullYear()+"-"+(parseInt(now.getMonth())+1)+"-"+i+"'>"+i+"</a></li>";
  }else{
   lis += "<li><a href=javascript:void(0) onclick='_selectThisDay(this)' title='"+now.getFullYear()+"-"+(parseInt(now.getMonth())+1)+"-"+i+"'>"+i+"</a></li>";
  }
  
}
var j=1;
for (i=thisMonthEndDay; i<6; i++){  // Next Month's Date
  lis += "<li class='nextMonthDate'>"+j+"</li>";
  j++;
}
lis += style;
var CalenderTitle = "<a href='javascript:void(0)' class='NextMonth' onclick=HS_calender(HS_DateAdd('m',1,'"+now.getFullYear()+"-"+now.getMonth()+"-"+now.getDate()+"'),this) title='Next Month'>&raquo;</a>";
CalenderTitle += "<a href='javascript:void(0)' class='LastMonth' onclick=HS_calender(HS_DateAdd('m',-1,'"+now.getFullYear()+"-"+now.getMonth()+"-"+now.getDate()+"'),this) title='Previous Month'>&laquo;</a>";
CalenderTitle += "<span class='selectThisYear'><a href='javascript:void(0)' onclick='CalenderselectYear(this)' title='Click here to select other year' >"+now.getFullYear()+"</a></span>年<span class='selectThisMonth'><a href='javascript:void(0)' onclick='CalenderselectMonth(this)' title='Click here to select other month'>"+(parseInt(now.getMonth())+1).toString()+"</a></span>月"; 
if (arguments.length>1){
  arguments[1].parentNode.parentNode.getElementsByTagName("ul")[1].innerHTML = lis;
  arguments[1].parentNode.innerHTML = CalenderTitle;
}else{
  var CalenderBox = style+"<div class='calender'><div class='calenderTitle'>"+CalenderTitle+"</div><div class='calenderBody'><ul class='day'><li>日</li><li>一</li><li>二</li><li>三</li><li>四</li><li>五</li><li>六</li></ul><ul class='date' id='thisMonthDate'>"+lis+"</ul></div><div class='calenderBottom'><a href='javascript:void(0)' class='closeCalender' onclick='closeCalender(this)'>&times;</a><span><span><a href=javascript:void(0) onclick='_selectThisDay(this)' title='"+todayString+"'>Today</a></span></span></div></div>";
  return CalenderBox;
}
}
function _selectThisDay(d){
var boxObj = d.parentNode.parentNode.parentNode.parentNode.parentNode;
  boxObj.targetObj.value = d.title;
  boxObj.parentNode.removeChild(boxObj);
}
function closeCalender(d){
var boxObj = d.parentNode.parentNode.parentNode;
  boxObj.parentNode.removeChild(boxObj);
}
function CalenderselectYear(obj){
  var opt = "";
  var thisYear = obj.innerHTML;
  for (i=1970; i<=2020; i++){
   if (i==thisYear){
    opt += "<option value="+i+" selected>"+i+"</option>";
   }else{
    opt += "<option value="+i+">"+i+"</option>";
   }
  }
  opt = "<select onblur='selectThisYear(this)' onchange='selectThisYear(this)' style='font-size:11px'>"+opt+"</select>";
  obj.parentNode.innerHTML = opt;
}
function selectThisYear(obj){
HS_calender(obj.value+"-"+obj.parentNode.parentNode.getElementsByTagName("span")[1].getElementsByTagName("a")[0].innerHTML+"-1",obj.parentNode);
}
function CalenderselectMonth(obj){
  var opt = "";
  var thisMonth = obj.innerHTML;
  for (i=1; i<=12; i++){
   if (i==thisMonth){
    opt += "<option value="+i+" selected>"+i+"</option>";
   }else{
    opt += "<option value="+i+">"+i+"</option>";
   }
  }
  opt = "<select onblur='selectThisMonth(this)' onchange='selectThisMonth(this)' style='font-size:11px'>"+opt+"</select>";
  obj.parentNode.innerHTML = opt;
}
function selectThisMonth(obj){
HS_calender(obj.parentNode.parentNode.getElementsByTagName("span")[0].getElementsByTagName("a")[0].innerHTML+"-"+obj.value+"-1",obj.parentNode);
}
function HS_setDate(inputObj){
var calenderObj = document.createElement("span");
calenderObj.innerHTML = HS_calender(new Date());
calenderObj.style.position = "absolute";
calenderObj.targetObj = inputObj;
inputObj.parentNode.insertBefore(calenderObj,inputObj.nextSibling);
}