Javascript 如何将用户时区转换为UTC？

我在我的网站上使用TimeIt代码，可以在以下位置找到：

这是代码的直接链接：

看起来是这样的：

//version 3. 2017-08-13
function timeit() {
  var next_run_array = []; //array of dates/time on a page used to rerun function if a change should happen during the session
  var curDate = new Date();
  Date.prototype.yyyymmdd = function() {
var mm = this.getMonth() + 1;
var dd = this.getDate();
return [this.getFullYear(),
  (mm > 9 ? '' : '0') + mm,
  (dd > 9 ? '' : '0') + dd
].join('-');
  };
  var curDateYMD = curDate.yyyymmdd();

  $('.timeit').each(function() {
var end = $(this).data('end'),
  start = $(this).data('start');
//check if date or time value has valid format and push it to the list of refresh anchors
var startDate = checkdate(start, this);
var endDate = checkdate(end, this);
nextrun(startDate);
nextrun(endDate);

//add a datetime when the page needs to be refreshed (now+24 hrs time span only)
function nextrun(date) {
  var nextruntimeout = date - curDate;
  if (nextruntimeout < 1000 * 60 * 60 * 24 && nextruntimeout > 1000) {
    next_run_array.push(nextruntimeout);    
  }
}

// Main Function 
//check if the evend outside of a desired time span
if (((startDate < endDate) && (startDate > curDate || endDate < curDate)) ||
  ((startDate > endDate) && (startDate >= curDate) && (endDate <= curDate))
) {
  $(this).addClass('hidden');
} else {
  $(this).removeClass('hidden');
}

//Support Functions
//correct data creation from a string. accepted format YYYY-MM-DD HH:MM
function parseISO8601(d) {
var isoExp = /^\s*(\d{4})-(\d\d)-(\d\d)?.(\d\d)?.(\d\d)\s*$/,
    date = new Date(NaN), 
    datenew,
    month,
    dateString=d.substr(0, d.indexOf(' ')); 
    parts = isoExp.exec(d);

if(parts) {  
  month = +parts[2];
  date.setFullYear(parts[1], month - 1, parts[3]);
  if(month != date.getMonth() + 1) {
    date.setTime(NaN);
  }
  date = new Date(parts[1], month - 1, parts[3],  parts[4], parts[5])
}
return date;
  }

  //unification of the date string to the format YYYY-MM-DD HH:MM
function checkdate(date, obj) {
  if (date) {
    //check if only time is set (HH:MM); if so, add today's date 
    if (String(date).length < 6 && String(date).indexOf(":") > -1) {
      date = curDateYMD + ' ' + String(date);
    }
    //check if only date is set; if so add 00:00 to the end of date
    if (String(date).indexOf(":") == -1) {
      date = date + ' 00:00';
    }
    //check if date is valid (avoid valid time)
    var res = date.split(":"),
      h = String(res.slice(0, 1)),
      hours = h.substr(h.length - 2),
      minutes = res.slice(1);
    var timetest = (hours < 24 && minutes < 60) ? true : false;

    //check if date is could be created from a value; if fails try to parse a string to a format
    var returndate = new Date(date);
    if (returndate == 'Invalid Date') {
      var returndate = parseISO8601(date);
    };


    if (returndate == 'Invalid Date' || !timetest) {
      //highlight the element if the is an error. use own \.error class if needed
      $(obj).addClass("error").attr('title', '"' + date + '" date is incorrect; please use YYYY-MM-DD HH:MM format');
    }
    return returndate.getTime();
  } else {
    //if datetime is not set, just return current date-time
    return curDate.getTime();
  }
}
  });

  /* Schedule next runs */
  if (next_run_array.length > 0) {  
var nextruntime = Math.min.apply(null, next_run_array);
console.log("next run of timeit function is in " +  nextruntime / 1000 + "seconds");
setTimeout(function() {
  timeit();
}, nextruntime);
  }
}
    timeit();

(

//版本3。2017-08-13
函数timeit（）{
var next_run_array=[]；//页面上的日期/时间数组，用于在会话期间发生更改时重新运行函数
var curDate=新日期（）；
Date.prototype.yyyymmdd=函数（）{
var mm=this.getMonth（）+1；
var dd=this.getDate（）；
返回[this.getFullYear（），
（毫米>9？“”：“0”）毫米+毫米，
（dd>9？“”：“0”）+dd
]。加入（“-”）；
};
var curDateYMD=curDate.yyyyymmd（）；
$（'.timeit'）。每个（函数（）{
var end=$（this）.data（'end'），
start=$（this）.data（'start'）；
//检查日期或时间值的格式是否有效，并将其推送到刷新锚点列表中
var startDate=检查日期（开始，此日期）；
var endDate=检查日期（结束，本）；
nextrun（起始日期）；
nextrun（结束日期）；
//添加需要刷新页面的日期时间（现在仅限24小时）
函数nextrun（日期）{
var nextruntimeout=date-curDate；
如果（下一次超时<1000*60*60*24和下一次超时>1000）{
下一步运行数组。推送（nextruntimeout）；
}
}
//主要功能
//检查均匀度是否超出所需的时间范围
如果（（开始日期<结束日期）和&（开始日期>截止日期| |结束日期<截止日期））||
（（startDate>endDate）&&&（startDate>=curDate）&&（endDate由于Weebly的原因，您不能使用服务器端脚本…您将不得不依赖于客户端的时钟，它可以调整。并且
隐藏的
类可以很容易地删除…但似乎您没有选择

现在，我建议你忘记这个插件

当涉及到JavaScript/jQuery中的日期时，我总是建议使用非常易于使用（您将不再需要执行复杂的计算）且有完整文档记录的日期，这样您就可以随心所欲了

在这里，基于数据属性中的开始/结束日期的内容隐藏如下所示：

//version 3. 2017-08-13
function timeit() {
  var next_run_array = []; //array of dates/time on a page used to rerun function if a change should happen during the session
  var curDate = new Date();
  Date.prototype.yyyymmdd = function() {
var mm = this.getMonth() + 1;
var dd = this.getDate();
return [this.getFullYear(),
  (mm > 9 ? '' : '0') + mm,
  (dd > 9 ? '' : '0') + dd
].join('-');
  };
  var curDateYMD = curDate.yyyymmdd();

  $('.timeit').each(function() {
var end = $(this).data('end'),
  start = $(this).data('start');
//check if date or time value has valid format and push it to the list of refresh anchors
var startDate = checkdate(start, this);
var endDate = checkdate(end, this);
nextrun(startDate);
nextrun(endDate);

//add a datetime when the page needs to be refreshed (now+24 hrs time span only)
function nextrun(date) {
  var nextruntimeout = date - curDate;
  if (nextruntimeout < 1000 * 60 * 60 * 24 && nextruntimeout > 1000) {
    next_run_array.push(nextruntimeout);    
  }
}

// Main Function 
//check if the evend outside of a desired time span
if (((startDate < endDate) && (startDate > curDate || endDate < curDate)) ||
  ((startDate > endDate) && (startDate >= curDate) && (endDate <= curDate))
) {
  $(this).addClass('hidden');
} else {
  $(this).removeClass('hidden');
}

//Support Functions
//correct data creation from a string. accepted format YYYY-MM-DD HH:MM
function parseISO8601(d) {
var isoExp = /^\s*(\d{4})-(\d\d)-(\d\d)?.(\d\d)?.(\d\d)\s*$/,
    date = new Date(NaN), 
    datenew,
    month,
    dateString=d.substr(0, d.indexOf(' ')); 
    parts = isoExp.exec(d);

if(parts) {  
  month = +parts[2];
  date.setFullYear(parts[1], month - 1, parts[3]);
  if(month != date.getMonth() + 1) {
    date.setTime(NaN);
  }
  date = new Date(parts[1], month - 1, parts[3],  parts[4], parts[5])
}
return date;
  }

  //unification of the date string to the format YYYY-MM-DD HH:MM
function checkdate(date, obj) {
  if (date) {
    //check if only time is set (HH:MM); if so, add today's date 
    if (String(date).length < 6 && String(date).indexOf(":") > -1) {
      date = curDateYMD + ' ' + String(date);
    }
    //check if only date is set; if so add 00:00 to the end of date
    if (String(date).indexOf(":") == -1) {
      date = date + ' 00:00';
    }
    //check if date is valid (avoid valid time)
    var res = date.split(":"),
      h = String(res.slice(0, 1)),
      hours = h.substr(h.length - 2),
      minutes = res.slice(1);
    var timetest = (hours < 24 && minutes < 60) ? true : false;

    //check if date is could be created from a value; if fails try to parse a string to a format
    var returndate = new Date(date);
    if (returndate == 'Invalid Date') {
      var returndate = parseISO8601(date);
    };


    if (returndate == 'Invalid Date' || !timetest) {
      //highlight the element if the is an error. use own \.error class if needed
      $(obj).addClass("error").attr('title', '"' + date + '" date is incorrect; please use YYYY-MM-DD HH:MM format');
    }
    return returndate.getTime();
  } else {
    //if datetime is not set, just return current date-time
    return curDate.getTime();
  }
}
  });

  /* Schedule next runs */
  if (next_run_array.length > 0) {  
var nextruntime = Math.min.apply(null, next_run_array);
console.log("next run of timeit function is in " +  nextruntime / 1000 + "seconds");
setTimeout(function() {
  timeit();
}, nextruntime);
  }
}
    timeit();

(


$（文档）.ready（函数（）{
var utc_date=moment（）.utc（）.format（“YYYY-MM-DD HH:MM”）；//客户的日期/时间（utc）
$（“.timeit”）.each（函数（）{
var start=力矩（$（this）.data（“start”）.format（“YYYY-MM-DD HH:MM”）；
var end=力矩（$（此）.data（“end”）.format（“YYYY-MM-DD HH:MM”）；
console.log(（utc_date>start&&utc_datestart&&utc_dateThank，我真的很感谢您花时间研究这一点。不幸的是，我运行了代码，但它仍然无法与utc时间配合使用。波兰是12:39，英国是11:39。我将开始日期更改为2019-02-11 11:41，因此在接下来的2分钟内内容不应该可见，但不管怎么说。很抱歉…我更改了比较，所以它比较了日期对象中的字符串。我还颠倒了逻辑。我想我昨天累了！哈哈