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2回答
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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> -
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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相关分类
JavaScript