Javascript 循环 - 在 while 条件中添加一个 var？

Question

基本上，我想根据每个月的捐款来计算并显示达到某个点(储蓄余额)所需的月数。

这是我目前所拥有的:

function howLong(initial,interest,goal,added){
    var initialDeposit = parseInt(initial);
    var interestInt = parseInt(interest);
    var targetSaving = parseInt(goal);
    var contribution = parseInt(added);
    var monthCount = 0;
    while(initialDeposit <= targetSaving){
        monthCount++;
        initialDeposit+contribution
    }
    alert(monthCount)
}

这是我的 html 表单:

<form>
Initial Deposit:<br />
<input type="number" id="initial"><br /><br />
Interest:<br />
<input type="number" id="interest"><br /><br />
Target savings amount:<br />
<input type="number" id="goal"><br /><br />
Monthly Contribution:<br />
<input type="number" id="contribution"><br /><br />
<input type="button" value="How Long!?" onclick="howLong(document.getElementById('initial').value,document.getElementById('interest').value,document.getElementById('goal').value),document.getElementById('contribution').value">
</form>

Answer 1

您需要将contribution的值添加到initialDeposit。

initialDeposit += contribution;

另外一个问题，你的函数调用有错误

document.getElementById('goal').value),document.getElementById('contribution').value"
                                     ^ >>>>>>>>>>>>>>>> should go >>>>>>>>>>>>>>>>> ^

应该是

onclick="howLong(
    document.getElementById('initial').value,
    document.getElementById('interest').value,
    document.getElementById('goal').value,
    document.getElementById('contribution').value
)"

最后一轮括号提前结束。

function howLong(initial, interest, goal, added) {
  var initialDeposit = parseInt(initial);
  var interestInt = parseInt(interest);
  var targetSaving = parseInt(goal);
  var contribution = parseInt(added);
  var monthCount = 0;
  while (initialDeposit <= targetSaving) {
    monthCount++;
    initialDeposit += contribution;
  }
  alert(monthCount)
}

<form>
  Initial Deposit:<br />
  <input type="number" id="initial"><br /><br /> Interest:
  <br />
  <input type="number" id="interest"><br /><br /> Target savings amount:<br />
  <input type="number" id="goal"><br /><br /> Monthly Contribution:<br />
  <input type="number" id="contribution"><br /><br />
  <input type="button" value="How Long!?" onclick="howLong(document.getElementById('initial').value,document.getElementById('interest').value,document.getElementById('goal').value,document.getElementById('contribution').value)">
</form>