Question

我创建了一个从10:00开始倒数的倒数计时器，我希望倒数计时器在1分钟以下时将其删除第一个0。并在10秒以下添加结尾的零。

例如：“ 0:59”，我想删除0，因此应显示“：59”，然后“：9”应显示“：09”

说实话，我没有做太多尝试。.我认为也许可以用正则表达式来完成，但是我不确定如何做。

我的计时器：

const mins = 10;
// getting the exact time as of the page load
const now = new Date().getTime();
// the math that is done for the actual countdown. So 10*60*1000 + the time retrieved from the page load.
const deadline = mins * 60 * 1000 + now;

// This is a function, however it is a JavaScript method and calls a function.
setInterval(() => {
  // Gets the current time
  var currentTime = new Date().getTime();
  //   gets the 'distance' between the deadline(10 mins) and the current time
  var distance = deadline - currentTime;
  //   found out this method does the math for you, I had to look this up and research it on W3schools
  var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
  var seconds = Math.floor((distance % (1000 * 60)) / 1000);
  // Inserts the timer into the Span timer
  timeSpan.innerHTML = minutes + ':' + seconds;
  //   the interval is set to 1 sec, so the timer refreshes and counts down every second

  if (seconds < 0) {
    confirm('Alert For your User!');
    window.location.reload();
  }
}, 1000);

我没有添加任何内容作为开始方式，因为我不确定从哪里开始！任何帮助都会很棒。

Answer 1

您可以使用一些基本的if语句来完成此操作（请参见下文），但是正如评论中的人们所说的，将其读为:59而不是0:59

看起来很奇怪。

const timeSpan = document.querySelector('#test');
const mins = 10;
// getting the exact time as of the page load
const now = new Date().getTime();
// the math that is done for the actual countdown. So 10*60*1000 + the time retrieved from the page load.
const deadline = 62 * 1000 + now;

// This is a function, however it is a JavaScript method and calls a function.
setInterval(() => {
  // Gets the current time
  var currentTime = new Date().getTime();
  //   gets the 'distance' between the deadline(10 mins) and the current time
  var distance = deadline - currentTime;
  //   found out this method does the math for you, I had to look this up and research it on W3schools
  var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
  var seconds = Math.floor((distance % (1000 * 60)) / 1000);

  if (minutes > 0) {
     if(seconds < 10){
            timeSpan.innerHTML = minutes + ':0' + seconds;
      } else {
             // Inserts the timer into the Span timer
             timeSpan.innerHTML = minutes + ':' + seconds;
       }
 
  } else if(seconds < 10) {
   timeSpan.innerHTML = ':0' + seconds;
  } else {
    timeSpan.innerHTML = ':' + seconds;
  }

  //   the interval is set to 1 sec, so the timer refreshes and counts down every second

  if (seconds < 0) {
    confirm('Alert For your User!');
    window.location.reload();
  }
}, 1000);

<p id="test">
</p>

Answer 2

答案：

您可以使用简单的if语句在输出进入屏幕之前更改输出。

  // check if seconds is single digit
  if(seconds.toString().length === 1) { seconds = "0" + seconds }
  // check if minutes is zero ( which is falsy )
  if(!minutes) minutes = "";
  // Inserts the timer into the Span timer
  timeSpan.innerHTML = minutes + ':' + seconds;

您还可以声明一个变量来保存对interval的引用

// declare the interval as a variable so you can clear it!
let my_interval = setInterval(() => {

这使您可以在不再需要运行时清除它：

if (seconds < 0) {
    confirm('Alert For your User!');
    //clear the interval when it finishes!
    clearInterval(my_interval);
  }
}, 1000);

代码段：

let timeSpan = document.querySelector("#timeSpan");
const mins = 1;
// getting the exact time as of the page load
const now = new Date().getTime();
// the math that is done for the actual countdown. So 10*60*1000 + the time retrieved from the page load.
const deadline = mins * 60 * 1000 + now;

// This is a function, however it is a JavaScript method and calls a function.

// declare the interval as a variable so you can clear it!
let my_interval = setInterval(() => {
  // Gets the current time
  var currentTime = new Date().getTime();
  //   gets the 'distance' between the deadline(10 mins) and the current time
  var distance = deadline - currentTime;
  //   found out this method does the math for you, I had to look this up and research it on W3schools
  var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
  var seconds = Math.floor((distance % (1000 * 60)) / 1000);
  
  // check if seconds is single digit
  if(seconds.toString().length === 1) { seconds = "0" + seconds }
  // check if minutes is zero ( which is falsy )
  if(!minutes) minutes = "";
  // Inserts the timer into the Span timer
  timeSpan.innerHTML = minutes + ':' + seconds;
  
  //   the interval is set to 1 sec, so the timer refreshes and counts down every second

  if (seconds < 0) {
    confirm('Alert For your User!');
    //clear the interval when it finishes!
    clearInterval(my_interval);
  }
}, 1000);

删除倒数计时器中的0

2 个答案:

答案：

代码段：