javascript - 求和 html 输入中的数字，Javascript

Question

我刚刚开始学习编码，我才刚刚开始。 我正在尝试为我的工作编写这个计算器，我已经尝试了好几天，甚至进行了研究，但我就是无法让它工作。这可能是有史以来最简单的事情......我只是在函数的最深处!我多次更改此代码，我什至不知道我在哪里。我一团糟，救命啊!

function myF() {
  var a = document.getElementById("a").value;
  var b = document.getElementById("b").value;
  var c = document.getElementById("c").value;
  var d = document.getElementById("d").value;
  var e = document.getElementById("e").value;
  var f = document.getElementById("f").value;
  var g = document.getElementById("g").value;
  var h = document.getElementById("h").value;
  var i = document.getElementById("i").value;

  var tot = document.getElementById("result").value = a + b + c + d + e + f + g + h + i;
}

body {
  background: url(img/Construction-Wallpaper-8.jpg) no-repeat center center;
  background-size: 100% 100%;
}

form {
  width: 530px;
  align-content: center;
  margin: 0 auto;
  border: solid 1px darkslategrey;
  padding: 10px 10px 10px 10px;
  display: block;
}

input {
  float: right;
  clear: both;
  position: relative;
  top: -4;
}

label {
  padding: 8px 10px;
  font-family: "Gabriola Regular", arial, sans-serif;
  font-size: 18px;
  font-weight: bolder;
  color: black;
  display: block;
}

input#result {
  position: relative;
  right: 18px;
  top: 6px;
}

button#Total {
  position: relative;
  left: 10px;
  top: 5px;
  background: linear-gradient(to right, darkslategrey, white);
  font-family: "Gabriola Regular", arial, sans-serif;
  font-size: 25px;
  width: 100px;
  height: 30;
  text-align: center;
  text-transform: uppercase;
  box-shadow: 1px 1px 3px;
  border: solid 1px black;
}

button#Total:active {
  position: relative;
  top: 6px;
  cursor: pointer;
}

button#Total:hover {
  cursor: pointer;
}

p#title {
  font-size: 50px;
  text-align: center;
  padding: 16px 0 0 0;
  font-family: "Gabriola Regular", arial, sans-serif;
  color: #333;
  font-weight: bolder
}

img#Logo {
  width: 70px;
  display: inline-block;
  position: absolute;
  top: 8px;
  right: 9px;
}

p#Logo {
  font-family: "Gabriola Regular", arial, sans-serif;
  font-size: 20px;
  display: inline-block;
  width: 50px;
  height: 30px;
  position: absolute;
  top: -10px;
  right: 105px;
}

<p id="title">&#8226; Payment Schedule &#8226;</p>
<div id="companyName">
  <p id="Logo">Christopher Crawford Const.
  </p>
  <img src="img/Logo_Crawford1ps.png" id="Logo">
</div>


<form>
  <label>I.Downpayment 5/14 <input id="a" type="text"></label>
  <label>II.Progress payment end of week2, @15% 5/30<input id="b" type="text"> </label>
  <label>III.Progress payment end of week4, @15% 6/13<input id="c" type="text"></label>
  <label>IV.Progress payment end of week6, @15% 6/27<input id="d" type="text"></label>
  <label>V.Progress payment end of week8, @15% 7/11<input id="e" type="text"></label>
  <label id="f">VI.Progress payment end of week10, @15% 7/25<input id="f" type="text"></label>
  <label>VII.Progress payment end of week11, @7.5% 8/1<input id="g" type="text"></label>
  <label>VIII.Progress payment end of week12, @7.5% 8/8<input id="h" type="text"></label>
  <label>IX.Final Payment @10%<input id="i" type="text"></label>
  <button id="Total" value="Add Numbers" onclick="myF()">Total</button>
  <input type="text" id="result">
</form>

Answer 1

您可能遇到的问题是该值返回字符串，如果您使用 + 它将连接它们，为了求和您需要解析字符串。

您可以使用 +document.getElementById("a").value 或 parseInt 这样的技巧。如果值为 float，则使用 parseFloat。

function myF() {
  var a = parseInt(document.getElementById("a").value);
  var b = parseInt(document.getElementById("b").value);
  var c = parseInt(document.getElementById("c").value);
  var d = parseInt(document.getElementById("d").value);
  var e = parseInt(document.getElementById("e").value);
  var f = parseInt(document.getElementById("f").value);
  var g = parseInt(document.getElementById("g").value);
  var h = parseInt(document.getElementById("h").value);
  var i = parseInt(document.getElementById("i").value);

  var tot = document.getElementById("result").value = a + b + c + d + e + f + g + h + i;
}