JavaScript制作简易计算器（不用eval）

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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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