JavaScript制作简易计算器（不用eval）

本文实例为大家分享了js制作简易计算器的具体代码，供大家参考，具体内容如下

<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style type="text/css">
    * {
      padding: 0;
      margin: 0;
    }
    li {
      list-style: none;
    }
    body {
      background: #940032;
    }

    #counter {
      width: 500px;
      height: 420px;
      background: #939;
      margin: 50px auto 0;
      position: relative;
    }

    #counter h2 {
      line-height: 42px;
      padding-left: 15px;
      font-size: 14px;
      font-family: arial;
      color: #ff3333;
    }

    #counter a {
      font-weight: normal;
      text-decoration: none;
      color: #ff3333;
    }

    #counter a:hover {
      text-decoration: underline;
    }

    #bg {
      width: 280px;
      height: 200px;
      border: 3px solid #680023;
      background: #990033;
      filter: alpha(opacity=80);
      opacity: 0.8;
      position: absolute;
      left: 50%;
      top: 115px;
      margin-left: -141px;
    }

    #counter_content {
      width: 250px;
      position: absolute;
      top: 130px;
      left: 130px;
      z-index: 1;
    }

    #counter_content h3 {
      margin-bottom: 10px;
    }

    #counter_content h3 input {
      border: none;
      width: 223px;
      height: 30px;
      line-height: 30px;
      padding: 0 10px;
      background: url(img/ico.png) no-repeat;
      text-align: right;
      color: #333;
      font-size: 14px;
      font-weight: bold;
    }

    #counter_content div {
      width: 250px;
    }

    #counter_content input {
      width: 60px;
      height: 30px;
      line-height: 30px;
      float: left;
      background: url(img/ico.png) no-repeat -303px 0;
      text-align: center;
      color: #fff;
      cursor: pointer;
      margin: 0 1px 4px 0;
      border: 0;
    }

    #counter_content div > input:hover {
      background: url(img/ico.png) no-repeat -243px 0;
    }

    #counter p {
      width: 500px;
      position: absolute;
      bottom: 20px;
      left: 0;
      color: #ff3333;
      text-align: center;
      font-size: 12px;
    }
  </style>
</head>
<body>
<div id="counter">
  <h2>简易计算</h2>
  <div id="counter_content">
    <h3><input id="input1" type="text" value="0"/></h3>
    <div id="div1">
      <input type="button" value="7" onclick="kick('7')"/>
      <input type="button" value="8" onclick="kick('8')"/>
      <input type="button" value="9" onclick="kick('9')"/>
      <input type="button" value="+" onclick="kick('+')"/>
      <input type="button" value="4" onclick="kick('4')"/>
      <input type="button" value="5" onclick="kick('5')"/>
      <input type="button" value="6" onclick="kick('6')"/>
      <input type="button" value="-" onclick="kick('-')"/>
      <input type="button" value="1" onclick="kick('1')"/>
      <input type="button" value="2" onclick="kick('2')"/>
      <input type="button" value="3" onclick="kick('3')"/>
      <input type="button" value="*" onclick="kick('*')"/>
      <input type="button" value="0" onclick="kick('0')"/>
      <input type="button" value="C" onclick="kick('C')"/>
      <input type="button" value="=" onclick="kick('=')"/>
      <input type="button" value="/" onclick="kick('/')"/>
    </div>
  </div>
</div>
</body>
<script>
  var showInput = document.getElementById("input1");
  var isClear = false;
  var tempStr = "";
  var clacType = "";
  var isContinue = true;
  function kick(clickValue) {
    switch (clickValue) {
      case "=":
        if (tempStr != "" && clacType != "") {
          showInput.value = clac(tempStr, showInput.value, clacType);
          isContinue = false;
          clacType = "";
        }
        break;
      case "+":
      case "-":
      case "*":
      case "/":
        //如果预存的操作符不为空 表示表示连续操作
        if (clacType != "" && !isContinue) { //先执行计算
          tempStr = clac(tempStr, showInput.value, clacType);
          isClear = true;
          clacType = clickValue;
        } else {
          tempStr = showInput.value; //点击操作符之后 预存字符
          isClear = true;//表示点击了操作符
          clacType = clickValue;//预存操作符
        }
        isContinue = true;
        break;
      case "C":
        showInput.value = "0";
        isClear = false;
        tempStr = "";
        clacType = "";
        break;
      default://普通的数字按钮点击
        showInput.value = showInput.value == "0" ? "" : showInput.value;
        isContinue = false;
        if (isClear) {
          showInput.value = "";
          showInput.value += clickValue;
          isClear = false;
        } else {
          showInput.value += clickValue;
        }
        break;
    }
  }

  function clac(num1, num2, type) {
    switch (type) {
      case "+":
        return Number(num1) + Number(num2);
      case "-":
        return Number(num1) - Number(num2);
      case "*":
        return Number(num1) * Number(num2);
      case "/":
        return Number(num1) / Number(num2);
      default:
        break;
    }
   }
  </script>

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