javascript写计算器教程
基于JavaScript实现简易计算器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>
<style>
.op {
margin: 50px auto;
width: 300px;
height: 300px;
border: 1px solid orange;
background-color: lightskyblue;
border-radius: 50px;
}
input {
width: 210px;
height: 30px;
border-radius: 5px;
}
button {
width: 30px;
height: 30px;
border-radius: 10px;
}
</style>
</head>
<body>
<li class="op">
<h2 align="center">计算器</h2>
<form name="calculator">
<table align="center">
<tr>
<td>num1:</td>
<td><input type="text" name="num1"></td>
</tr>
<tr>
<td>num2:</td>
<td><input type="text" name="num2"></td>
</tr>
<tr>
<td colspan="2">         
<button type="button">+</button>
      
<button type="button">-</button>
      
<button type="button">*</button>
      
<button type="button">/</button>
</td>
</tr>
<tr>
<td>结果：</td>
<td><input type="text" name="result" disabled></td>
</tr>
</table>
</form>
</li>
<script>
//得到标签名下的所有元素对象，返回一个数组
let buttonArr = document.getElementsByTagName("button");
for (let but of buttonArr) {
but.addEventListener('click', function () {
let operator = this.innerHTML;
count(operator);
});
}
function count(operator) {
//得到form为calculator中name为num1的输入值
let num1 = parseFloat(document.calculator.num1.value);
let num2 = parseFloat(document.calculator.num2.value);
let result = '';
switch (operator) {
case '+':
result = num1 + num2;
break;
case '-':
result = num1 - num2;
break;
case '*':
result = num1 * num2;
break;
case '/':
if (num2 == 0) {
alert("除数不能为零");
return;
}
result = num1 / num2;
break;
}
//将结果赋值于属性名name为result的input框
document.calculator.result.value = result;
}
</script>
</body>
</html>
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持开心学习网。