JavaScript upTime函数-不识别变量的ID

JavaScript upTime function - Not recognizing ID of variable

本文关键字：变量 ID 识别 upTime 函数 JavaScript      更新时间：2023-09-26

我的目标是让calcyear (cyear)最初从值"8"开始。每当天数达到364时，我希望从这个8值中减去一个值"1"，直到它达到零。

由于某些原因，p id似乎不能识别日历id…或者它可能是，但是代码是错误的?

整个代码:

<html>
<style>
#countup p {
display: inline-block;
padding: 0px;
margin: 0 0 10px;
}
#paragraph2 p {
display: inline-block;
padding: 0px;
margin: 0 0 10px;
}
</style>
<div id="countup">
  We are in day
  <p id="days">00</p>
  <p class="timeRefDays">of the calendar. This day has been going on for </p>
  <p id="hours">00</p>
  <p class="timeRefHours">hours, </p>
  <p id="minutes">00</p>
  <p class="timeRefMinutes">minutes, and </p>
  <p id="seconds">00</p>
  <p class="timeRefSeconds"> seconds.</p>
</div>
<div id="paragraph2">
<p>We are in month</p>
<p id="months">00</p>
<p>of the year.</p>
</div>
<div id="paragraph2">
<p>In </p>
<p id="calcyear">0</p>
<p> years an intercalation week will be added.</p>
</div>
<script>
window.onload=function() {
  upTime('mar,20,2016,00:00:00'); 
}
function upTime(countTo) {
  now = new Date();
  countTo = new Date(countTo);
  difference = (now-countTo);
  days=Math.floor(difference/(60*60*1000*24)*1);
  hours=Math.floor((difference%(60*60*1000*24))/(60*60*1000)*1);
  mins=Math.floor(((difference%(60*60*1000*24))%(60*60*1000))/(60*1000)*1);
  secs=Math.floor((((difference%(60*60*1000*24))%(60*60*1000))%(60*1000))/1000*1);
  mons=Math.floor(difference/(24*60*60*1000*24)*1);
  cyear= 8
  years=Math.floor(days / 364)
  if (years > 1){ cyear = cyear - 1}
  document.getElementById('days').firstChild.nodeValue = days;
  document.getElementById('hours').firstChild.nodeValue = hours;
  document.getElementById('minutes').firstChild.nodeValue = mins;
  document.getElementById('seconds').firstChild.nodeValue = secs;
  document.getElementById('months').firstChild.nodeValue = mons;
  document.getElementById('years').firstChild.nodeValue = years;
  document.getElementById('calcyear').firstChild.nodeValue = cyear;

  clearTimeout(upTime.to);
  upTime.to=setTimeout(function(){ upTime(countTo); },1000);
}
</script>
</html>

问题出在这段代码上:

document.getElementById('years').firstChild.nodeValue = years;

在你的HTML中没有一个id为'years'的元素，这样你会收到错误:

Uncaught TypeError: Cannot read property 'firstChild' of null

由于没有id为'years'的元素，那么document.getElementById('years')将返回null。此错误还会停止执行，因此下一行将无法运行。因此，因为它是在calcyear之后没有更新。

document.getElementById('years').firstChild.nodeValue = years; // Stops
document.getElementById('calcyear').firstChild.nodeValue = cyear; // Not ran

似乎你想添加它，但可能忘记了:

<div id="paragraph2">
<p>We are in month</p>
<p id="months">00</p>
<p>of the year </p>
<p id="years">00</p>  <!-- Added line -->
</div>

没有id为years的元素，所以您的代码停在那里。

只要在你的代码中添加<p id="years">0</p>，它就会运行。

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