JavaScript实现简易计算器小功能

Z时代
2024-01-10
分类：IT

本文实例为大家分享了JavaScript实现简易计算器的具体代码，供大家参考，具体内容如下


<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>计算器</title>
</head>
<body>
<!--页面布局-->
<input type="text" id="num1" placeholder="请输入第一个数字"/>
<input type="text" id="operator" placeholder="请输入运算符">
<input type="text" id="num2" placeholder="请输入第二个数字"/>
<input type="button" onclick="count()" value="计算"/><br/>
<span>计算结果：</span><span id="result"></span>
<!--JavaScript-->
<script>
  function count() {
    var num1 = document.getElementById("num1").value;
    var num2 = document.getElementById("num2").value;
    var operator = document.getElementById("operator").value;
    var num = "";
    //判断输入的两个数字是否为数字,如果为数字，返回结果为false
    var num1 = parseFloat(num1);
    var num2 = parseFloat(num2);
    var isNotNumber = isNaN(num1) || isNaN(num2);
    if (!isNotNumber) {
      switch (operator) {
        case "+":
          num = num1 + num2;
          break;
        case "-":
          num = num1 - num2;
          break;
        case "*":
          num = num1 * num2;
          break;
        case "/":
          if (num2 == 0) {
            // 除数不能为0
            alert("除数不能为0");
          } else {
            num = num1 / num2;
            break;
          }
        default:
          alert("请输入正确的运算符！！！");
      }
      num = num.toFixed(2);
      document.getElementById("result").innerText = num;
    } else {
      alert("请输入数字！！！")
    }
  }
</script>
</body>
</html>