<SCRIPT>
  window.onload = () => {
    startTime();
  }

  function startTime(){
    var time= new Date();
    hours= time.getHours();
    mins= time.getMinutes();
    secs= time.getSeconds();
    startTime= hours*3600+mins*60+secs;
    closeTime = startTime + 5;
    document.querySelector(".closetime").innerText = "Start Time : "+hours+" : "+mins+" : "+secs+" : ( closeTime : "+closeTime+")";
    Timer();
  }

  function Timer(){
    var time= new Date();
    hours= time.getHours();
    mins= time.getMinutes();
    secs= time.getSeconds();
    curTime=hours*3600+mins*60+secs
    if (curTime>=closeTime){
      console.log("function_start!!");
    }else{
      window.setTimeout("Timer()",1000);
      document.querySelector(".timer").innerText = "Timer : "+hours+" : "+mins+" : "+secs+" : ("+curTime+")";
    }
  }
</SCRIPT>