【javascript】有计算功能的简易计算器

阿里云国内75折回扣微信号：monov8

阿里云国际，腾讯云国际，低至75折。AWS 93折免费开户实名账号代冲值优惠多多微信号：monov8 飞机：@monov6

在这里插入图片描述
外观不满意可以自行修改。
主要用到的有grid布局 js原生阿里字体图标 eval函数

eval() 函数计算 JavaScript 字符串并把它作为脚本代码来执行。

如果参数是一个表达式eval() 函数将执行表达式。如果参数是Javascript语句eval()将执行 Javascript 语句。
代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>计算器</title>
</head>
<link rel="stylesheet" href="fonts/iconfont.css">

    <style>
        *{padding:0; margin:0;}
        #count{
            width: 258px;
            height: 452px;
            background-color: #fff;
            margin: 100px auto;
            border-radius:20px;
            border:2px solid black;
            box-shadow: 0 0 3px 1px black;
            background-color: rgba(43, 10, 10,0.1);
        }
        .number{
            display: grid;
            gap:5px;
        grid-auto-flow: row dense;
        grid-template-rows: repeat(5,60px);
        grid-template-columns: repeat(4,50px);
        justify-content: center;

        }
        .cbt{
            text-align: center;
            font-size: 20px;
            border:1px solid black;
            cursor: pointer;
            color:rgb(16, 15, 14);
            font-weight: 600;
           text-align: center;
           line-height: 60px;
           font-family: Arial, Helvetica, sans-serif;
           box-shadow: 0 0 3px 1px black;
         background-color: rgba(43, 10, 10,0.1);
         border-radius: 10px;
        }
        #count #inp{
            font-size: 20px;
            color:#fff;
            line-height: 40px;
            text-align: center;
            font-weight: 800;
            margin-top:30px;
            margin-left:18px;
            width: 220px;
            height: 40px;
            /* box-shadow: 0 0 3px 1px black; */
            border-radius: 10px;
            margin-bottom:10px;
         background-color: rgba(117, 223, 18, 0.2);

        }
        #dy{
            height: 123px;
            line-height: 123px;
        }
        .green{
        color:rgb(23, 70, 23);
        background: gray;
        }
        .blue{
            color:rgb(36, 36, 67);
            background: yellow;
        }
    </style>
<body>
<div id="count">
    <input type="text" id="inp">
    <div class="number">
    <span class="cbt green" onclick="clickbt()">C</span>
    <span class="cbt green"onclick="clickbt()">/</span>
    <span class="cbt green"onclick="clickbt()">*</span>
    <span class="iconfont 
    icon-backspace cbt blue"onclick="back()" id="back"></span>
    <span class="cbt"onclick="clickbt()">7</span>
    <span class="cbt"onclick="clickbt()">8</span>
    <span class="cbt"onclick="clickbt()">9</span>
    <span class="cbt blue"onclick="clickbt()">-</span>
    <span class="cbt"onclick="clickbt()">4</span>
    <span class="cbt"onclick="clickbt()">5</span>
    <span class="cbt"onclick="clickbt()">6</span>
    <span class="cbt blue"onclick="clickbt()">+</span>
    <span class="cbt"onclick="clickbt()">1</span>
    <span class="cbt"onclick="clickbt()">2</span>
    <span class="cbt"onclick="clickbt()">3</span>
    <span id="dy" class="cbt blue"onclick="getCount()">=</span>
    <span class="cbt"onclick="clickbt()">%</span>
    <span class="cbt"onclick="clickbt()">0</span>
    <span class="cbt"onclick="clickbt()">.</span>
</div>
</div>
</body>
<script>
    var backs=document.getElementById("back");
var einp=document.querySelector("#inp");
var clickbt=function(e) {
    //取得点击的对象元素
    var tg=event.target;
    // 让输入框的值进行相加
    // einp.value=einp.value+tg.innerHTML;
    if(tg.innerHTML=="C"){
        einp.value=" ";}
        else  {
       
einp.value=einp.value+tg.innerHTML;
    }
}
//通过eval函数实现求和
var getCount=function() {
    einp.value=eval(einp.value);
}
var back=function(e) {
    var tg=event.target;
    if(tg.innerHTML==backs.innerHTML){
        if(einp.value !==0){
           einp.value=einp.value.substring(0, einp.value.length - 1);
        }
    }
}
</script>
</html>