Javascript - Cooldown

Im making a web game.

I want to have a cooldown on some actions, but the problem now is that if you refresh the page the cooldown is away. I know i could get the date, and then store the date in localstorage. But i cant figure it out.

function cooldown(){
    var timeleft = 0;
    timeleft = document.getElementById('lagre02').textContent;
    timeleft = parseInt (timeleft, 10);
    localStorage.setItem("tid", timeleft);
    timeleft = localStorage.getItem("tid");
    
    if (timeleft > 0) {
        var myNode = document.getElementById("info01");
        while (myNode.firstChild) {
                myNode.removeChild(myNode.lastChild);
              }
        document.getElementById("info01").innerHTML = "<div class='d-flex flex-column justify-content-center align-items-center w-100 h-100'><p id='p_01'>Du har fortsett:</p> <br> <p class='text-center fs-3' id='countdown'></p> <br> <p id='p_01'>sekunder igjen.</p></div>"
        var timer = setInterval(function(){
            if(timeleft <= 0){
              clearInterval(timer);
              location.reload();
            } else {
              document.getElementById("countdown").innerHTML = timeleft;
            }
            timeleft -= 1;
          }, 1000);
    }
}

The var "timeleft" is set when the action is complete.

I think the best soulution is to use server side date, but i cant figure it out.