如何检索表单值，对该表单值执行操作并在<p>标记中显示？

如何检索表单值，对该表单值执行操作并在<p>标记中显示？

我想从表单控件类型=“数字”中获取一个数字，将其进行比较，然后如果条件确定，则对其进行乘法和除法。之后，我想将结果显示为<p>标签的内容。如何做到这一点？

到目前为止，这是我尝试过的：

let amount = document.getElementById(".amount");

let marginAmount = document.getElementById(".marginAmount")

let submit = document.getElementById(".submit");

submit.addEventListener('click', calcAmount);

const calcLevel1 = amount * 7 / 100;

function calcAmount() {

let userAmount = Number(amount.value);

let level1 = 351;

if (userAmount <= level1) {

marginAmount.textContent = calcLevel1.value;

}

}

<div class="form">

<label for="points amount">Entrez un montant en points</label>

<input type="number" class="amount-enter" id="amount">

<input type="submit" value="Montant marge additionnelle" id="submit" class="submit-enter">

</div>

<p id="marginAmount" class="enter-margin"></p>

芜湖不芜

浏览 177回答 2

2回答

郎朗坤

这是已更正的代码，有。我还添加math.round了哪些要删除的内容以获得四舍五入的结果：<html><head>  <script>    function calcAmount() {      let userAmount = document.getElementById("amount").value;      let level1 = 351;      if (userAmount <= level1) {        document.getElementById("marginAmount").textContent = Math.round(userAmount * 7) / 100;      } else {        document.getElementById("marginAmount").textContent = "Amount is > 351";      }    }  </script></head><body>  <div class="form">    <label for="points amount">Entrez un montant en points</label>    <input type="number" class="amount-enter" id="amount">    <input type="submit" value="Montant marge additionnelle" id="submit" class="submit-enter" onclick="calcAmount()">  </div>  <p id="marginAmount" class="enter-margin"></p></body>

0

0

慕桂英4014372

三件事：您.在ID选择器中没有这些选择器（它们应该存在，#但只能在一种querySelector方法中使用）。您正在calcLevel1直接计算，这意味着0 * 7 / 100是0。你需要计算calcLevel1用amount.value，这意味着你可以删除calcLevel1.value，当你设置textContent的段落。我还添加了一条else语句，以便textContent在该语句为false时将其清空。let amount = document.getElementById("amount");let marginAmount = document.getElementById("marginAmount")let submit = document.getElementById("submit");submit.addEventListener('click', calcAmount);function calcAmount() {  const calcLevel1 = amount.value * 7 / 100;  let userAmount = Number(amount.value);  let level1 = 351;  if (userAmount <= level1) {    marginAmount.textContent = calcLevel1;  } else {    marginAmount.textConten = "";  }}<div class="form">  <label for="points amount">Entrez un montant en points</label>  <input type="number" class="amount-enter" id="amount">  <input type="submit" value="Montant marge additionnelle" id="submit" class="submit-enter"></div><p id="marginAmount" class="enter-margin"></p>

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