页面刷新后如何继续计时？

Question

目前，我的代码中有这个 JavaScript

function startTimer(duration, display) {
  var timer = duration,
      minutes, seconds;
  setInterval(function() {
    minutes = parseInt(timer / 60, 10);
    seconds = parseInt(timer % 60, 10);

    minutes = minutes < 10 ? "0" + minutes : minutes;
    seconds = seconds < 10 ? "0" + seconds : seconds;

    display.textContent = minutes + ":" + seconds;

    if (--timer < 0) {
      timer = 0;
    }
  }, 1000);
}

window.onload = function() {
  var fiveMinutes = 60 * 0.18,
      display = document.querySelector('#time');
  startTimer(fiveMinutes, display); //`enter code here`
};

<div id="time"></div>

刷新时如何保持计时器运行？使用 cookie 是唯一的方法吗？

Answer 1

如果你的服务器端没有数据库之类的东西，我认为 cookie 是你最好的选择and/or用户没有登录：

这可能会帮助您开始，根据

定义设置和获取 cookie 函数

设置

 function setCookie(cname, cvalue, exdays) {
  var d = new Date();
  d.setTime(d.getTime() + (exdays*24*60*60*1000));
  var expires = "expires="+d.toUTCString();
  document.cookie = cname + "=" + cvalue + "; " + expires;
 }

得到

function getCookie(cname) {
 var name = cname + "=";
 var ca = document.cookie.split(';');
 for(var i=0; i<ca.length; i++) {
    var c = ca[i];
    while (c.charAt(0)==' ') c = c.substring(1);
    if (c.indexOf(name) == 0) return c.substring(name.length,c.length);
 }
 return "";
}

在您的文档中的某处，也许在您的计时器中，将您的 cookie 设置为：

setCookie("minutes", minutes.toString(), 1);
setCookie("seconds", seconds.toString(), 1);

然后在加载事件的某处通过 get 函数设置变量，例如：

minutes = getCookie("minutes");
seconds = getCookie("seconds");

在此处阅读更多内容 http://www.w3schools.com/js/js_cookies.asp

Answer 2

那只是关于如何制作 cookie 的提示，这里是工作代码。在此处查看 fiddle：https://jsfiddle.net/edencorbin/hht4yqka/1/ 您需要调整计时器，我已将其设置为 10:00。

  <script>
  var minutes = 0;
  var seconds = 0;
  function startTimer(duration, display) {
    var timer = duration,
        minutes, seconds;
    setInterval(function() {
      minutes = parseInt(timer / 60, 10);
      seconds = parseInt(timer % 60, 10);

      minutes = minutes < 10 ? "0" + minutes : minutes;
      seconds = seconds < 10 ? "0" + seconds : seconds;

      display.textContent = minutes + ":" + seconds;

      setCookie("minutes", minutes.toString(), 1);
      setCookie("seconds", seconds.toString(), 1);

      if (--timer < 0) {
        timer = 0;
      }
    }, 1000);
  }


  window.onload = function() {
     var minutes_data = getCookie("minutes");
     var seconds_data = getCookie("seconds");
     var timer_amount = (60*10); //default
      if (!minutes_data || !seconds_data){
        //no cookie found use default
      }
      else{
        timer_amount = parseInt(minutes_data*60)+parseInt(seconds_data)
      }

    var fiveMinutes = timer_amount,
        display = document.querySelector('#time');
    startTimer(fiveMinutes, display); //`enter code here`
  };

   function setCookie(cname, cvalue, exdays) {
    var d = new Date();
    d.setTime(d.getTime() + (exdays*24*60*60*1000));
    var expires = "expires="+d.toUTCString();
    document.cookie = cname + "=" + cvalue + "; " + expires;
   } 

   function getCookie(cname) {
   var name = cname + "=";
   var ca = document.cookie.split(';');
   for(var i=0; i<ca.length; i++) {
      var c = ca[i];
      while (c.charAt(0)==' ') c = c.substring(1);
      if (c.indexOf(name) == 0) return c.substring(name.length,c.length);
   }
   return "";
  } 

  </script>

  <div id="time"></div>

页面刷新后如何继续计时？

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