向Java倒数计时器添加分钟还是秒？

Question

我有一个JavaScript倒数计时器。 我需要做的是能够在倒数计时器运行时向计时器添加1分钟或几秒钟！

例如：如果我将分钟设置为1分钟并按“开始”按钮，则倒数计时器将按原样启动，但如果我在计时器运行时再增加一分钟，即32秒时，则不会添加该值到当前数字，它会继续倒计时添加的前1分钟的剩余时间，并且由于某种原因，它只会加快倒计时！

希望我不要让你们感到困惑。 这是代码：

<form>
Minutes: <input type="text" id="mns" name="mns" value="0" size="3" maxlength="3" /> &nbsp; &nbsp; Seconds: <input type="text" id="scs" name="scs" value="0" size="2" maxlength="2" /><br/>
<input type="button" id="btnct" value="START" onclick="countdownTimer()"/>
</form>
Countdown Timer: &nbsp; <span id="showmns">00</span>:<span id="showscs">00</span>
<script type="text/javascript"><!--
    /* Function to display a Countdown timer with starting time from a form */
// sets variables for minutes and seconds
var ctmnts = 0;
var ctsecs = 0;
var startchr = 0;       // used to control when to read data from form

function countdownTimer() {
  // http://coursesweb.net/javascript/
  // if $startchr is 0, and form fields exists, gets data for minutes and seconds, and sets $startchr to 1
  if(startchr == 0 && document.getElementById('mns') && document.getElementById('scs')) {
    // makes sure the script uses integer numbers
    ctmnts = parseInt(document.getElementById('mns').value) + 0;
    ctsecs = parseInt(document.getElementById('scs').value) * 1;

    // if data not a number, sets the value to 0
    if(isNaN(ctmnts)) ctmnts = 0;
    if(isNaN(ctsecs)) ctsecs = 0;

    // rewrite data in form fields to be sure that the fields for minutes and seconds contain integer number
    document.getElementById('mns').value = ctmnts;
    document.getElementById('scs').value = ctsecs;
    startchr = 1;
  }

  // if minutes and seconds are 0, sets $startchr to 0, and return false
  if(ctmnts==0 && ctsecs==0) {
    startchr = 0;
    document.getElementById('btnct').removeAttribute('disabled');     // remove "disabled" to enable the button

    /* HERE YOU CAN ADD TO EXECUTE A JavaScript FUNCTION WHEN COUNTDOWN TIMER REACH TO 0 */

    return false;
  }
  else {
    // decrease seconds, and decrease minutes if seconds reach to 0
    ctsecs--;
    if(ctsecs < 0) {
      if(ctmnts > 0) {
        ctsecs = 59;
        ctmnts--;
      }
      else {
        ctsecs = 0;
        ctmnts = 0;
      }
    }
  }

  // display the time in page, and auto-calls this function after 1 seccond
  document.getElementById('showmns').innerHTML = ctmnts;
  document.getElementById('showscs').innerHTML = ctsecs;
  setTimeout('countdownTimer()', 1000);
}
//-->
</script>

任何帮助，将不胜感激。

这是小提琴

Answer 1

将计数器编号视为要经过的总秒数的单个值，并且仅在转换为当前值和/或从当前值转换时（例如，在获取初始输入时或在显示当前值时）才担心分钟和秒。

请参见http://jsfiddle.net/alnitak/aBWce/，了解一个有效的示例，该示例避免了需要检查每一分钟的结束时间或特殊情况下的填充数字。

顺便说一句，您的return false行是空操作-回调函数的返回值将被忽略。