Question

我已编写代码来计算两次之间的时间，这是我的代码

 <html>
<head>
<script>

// java描述

 calculateDiff();

function calculateDiff(){
var _start = document.getElementsByName("usr").value;
var _end = document.getElementsByName("usr2").value;

    _start_time = parseAMDate(_start);
    _end_time = parseAMDate(_end);

    if (_end_time < _start_time){
        _end_time = parseAMDate(_end,1);
    }

    var difference= _end_time - _start_time;

    var hours = Math.floor(difference / 36e5),
        minutes = Math.floor(difference % 36e5 / 60000);
    if (parseInt(hours) >= 0 ){
        if (minutes == 0){
            minutes = "00";
        }
        alert(hours+":"+minutes);
    }
}

function parseAMDate(input, next_day) {

    var dateReg = /(\d{1,2}):(\d{2})\s*(AM|PM)/;

    var hour, minute, result = dateReg.exec(input);

    if (result) {
        hour = +result[1];
        minute = +result[2];

        if (result[3] === 'PM' && hour !== 12) {
            hour += 12;
        }
    }
    if (!next_day) {
        return new Date(1970, 01, 01, hour, minute).getTime();
    }else{
        return new Date(1970, 01, 02, hour, minute).getTime();
    }
}

//形式

</script>
</head>
<body>

<form> 
Select  start time:<input type="time" name="usr" id="startTime">
Select  end time: <input type="time" name="usr2" id="endTime">
<input type="button" value="cal" onclick="calculateDiff()">
</form>
</body>
</html>

如果我正在执行此操作，我无法获得输出，请帮助我

当我运行此代码时，我正在退出

     calculateDiff();

     function calculateDiff(){
    _start = "01:00 AM";
    _end = "02:00 AM";

    _start_time = parseAMDate(_start);
    _end_time = parseAMDate(_end);

    if (_end_time < _start_time){
        _end_time = parseAMDate(_end,1);
    }

    var difference= _end_time - _start_time;

    var hours = Math.floor(difference / 36e5),
        minutes = Math.floor(difference % 36e5 / 60000);
    if (parseInt(hours) >= 0 ){
        if (minutes == 0){
            minutes = "00";
        }
        alert(hours+":"+minutes);
    }
}

function parseAMDate(input, next_day) {

    var dateReg = /(\d{1,2}):(\d{2})\s*(AM|PM)/;

    var hour, minute, result = dateReg.exec(input);

    if (result) {
        hour = +result[1];
        minute = +result[2];

        if (result[3] === 'PM' && hour !== 12) {
            hour += 12;
        }
    }
    if (!next_day) {
        return new Date(1970, 01, 01, hour, minute).getTime();
    }else{
        return new Date(1970, 01, 02, hour, minute).getTime();
    }
}

如何获取上述代码？

Answer 1

问题是_start和_end是undefined：

var _start = document.getElementsByName("usr").value;
var _end = document.getElementsByName("usr2").value;

在你使用之前

：

_start = "01:00 AM";
_end = "02:00 AM";

所以它有效。

document.getElementsByName()正在返回一个数组：

document.getElementsByName("usr")[0].value

＆＃13;

<html>

<head>
  <script>
    //javascript


    window.onload = calculateDiff;

    function calculateDiff() {
      var _start = document.getElementsByName("usr")[0].value;
      var _end = document.getElementsByName("usr2")[0].value;
      
      
      _start_time = parseAMDate(_start);
      _end_time = parseAMDate(_end);

      if (_end_time < _start_time) {
        _end_time = parseAMDate(_end, 1);
      }

      var difference = _end_time - _start_time;

      var hours = Math.floor(difference / 36e5),
        minutes = Math.floor(difference % 36e5 / 60000);
      if (parseInt(hours) >= 0) {
        if (minutes == 0) {
          minutes = "00";
        }
        alert(hours + ":" + minutes);
      }
    }

    function parseAMDate(input, next_day) {

      var dateReg = /(\d{1,2}):(\d{2})\s*(AM|PM)/;

      var hour, minute, result = dateReg.exec(input);

      if (result) {
        hour = +result[1];
        minute = +result[2];

        if (result[3] === 'PM' && hour !== 12) {
          hour += 12;
        }
      }
      if (!next_day) {
        return new Date(1970, 01, 01, hour, minute).getTime();
      } else {
        return new Date(1970, 01, 02, hour, minute).getTime();
      }
    }

     //form
  </script>
</head>

<body>

  <form>
    Select start time:
    <input type="time" name="usr" id="startTime">Select end time:
    <input type="time" name="usr2" id="endTime">
    <input type="button" value="cal" onclick="calculateDiff()">
  </form>
</body>

</html>

＆＃13;

如何计算两次之间的时差？

1 个答案: