날짜 계산관련 스크립트

function setDateRange(selected_date_range){
  if(selected_date_range.value=="ALL"){
   document.search.startDate.value = "";
   document.search.endDate.value = "";
  }
  else if(selected_date_range.value=="WEEK"){
   document.search.startDate.value = getNextDate(-7);
   document.search.endDate.value = getNextDate(0);
  }
  else if(selected_date_range.value=="MONTH"){
   document.search.startDate.value = getNextDate(-30);
   document.search.endDate.value = getNextDate(0);
  }else  if(selected_date_range.value=="SET"){
   document.search.startDate.value = getNextDate(-(365*5));//기본 5년전부터.
   document.search.endDate.value = getNextDate(0);
  }
 }
 
 function setDateRangeButton(){
  if(document.search.startDate.value == ""){
   document.search.startDate.value = getNextDate(-(365*5));
   document.search.endDate.value = getNextDate(0);
  }
  document.search.date_range[3].checked= "checked";
 }
 
 function getNextDate(t){
  var current_time = new Date();
  var result = current_time.valueOf()+1000*60*60*24*(t);
  var result_time = new Date(result);
  var yy = result_time.getFullYear();
  var mm = result_time.getMonth()+1;
  if(mm<10)
   mm = "0"+mm;
  var dd = result_time.getDate();
  var date_string = yy+"-"+mm+"-"+dd;
  return date_string;
 }