function autoCountDate(currentDate,num,itemId){
	var aDate,tempDate,resultDate;
	aDate = parseDate(currentDate);
	var longValue = aDate.getTime() + num*1000*24*60*60;
	resultDate = new Date(longValue);
	document.getElementById(itemId).value = resultDate.format('yyyy-MM-dd');
}
Date.prototype.format = function(format){   
   var o = {   
     "M+" : this.getMonth()+1, //month   
     "d+" : this.getDate(),    //day   
     "h+" : this.getHours(),   //hour   
     "m+" : this.getMinutes(), //minute   
     "s+" : this.getSeconds(), //second   
     "q+" : Math.floor((this.getMonth()+3)/3), //quarter   
     "S" : this.getMilliseconds() //millisecond   
   }   
   if(/(y+)/.test(format)) format=format.replace(RegExp.$1,   
     (this.getFullYear()+"").substr(4 - RegExp.$1.length));   
   for(var k in o)if(new RegExp("("+ k +")").test(format))   
     format = format.replace(RegExp.$1,   
       RegExp.$1.length==1 ? o[k] :    
         ("00"+ o[k]).substr((""+ o[k]).length));   
   return format;   
}

function parseDate(str){
  if(typeof str == 'string'){
    var results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) *$/);
    if(results && results.length>3)
      return new Date(results[1],results[2] -1,results[3]);
    results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) +(\d{1,2}):(\d{1,2}):(\d{1,2}) *$/);
    if(results && results.length>6)
      return new Date(results[1],results[2] -1,results[3],results[4],results[5],results[6]);
    results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) +(\d{1,2}):(\d{1,2}):(\d{1,2})\.(\d{1,9}) *$/);
    if(results && results.length>7)
      return new Date(results[1],results[2] -1,results[3],results[4],results[5],results[6],results[7]);
  }
  return null;
}