DDR爱好者之家

JavaScript实现简单计算器
站长资源 2025/10/28 佚名
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DDR爱好者之家 Design By 杰米

适合初学者参考的简易计算器，里面没有太多的难以理解的方法，使用的是最基础的JS语法解决式子的运算问题，同时处理了式子中的运算优先级。

实现思路

1、通过绑定点击事件实现待计算式子的输入
2、遍历原式子，读取式子中乘除运算符的位置
3、优先处理乘除取余运算
4、处理加减运算
5、返回结果

代码：

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
 <!-- 计算器 -->
 <style>
    .work2{
      width: 500px;
      margin-top: 50px;
    }
    h2{
      color: #333;
    }
    #work2Article1{
      width: 100%;
      height: 200px;
      background: #cccccc;
      font-size: 20px;
    }
    #work2Article2{
      width: 100%;
      height: 400px;
      background: #cccccc;
    }
    #work2Article2 button{
      width: 24.1%;
      height: 20%;
      color: #333;
      background: #999;
    }
    .work2 button{
      font-size: 20px;
    }
    
  </style>
  <section class="work2">
    <h2>计算器</h2>
    <article id="work2Article1">
  
    </article>
    <article id="work2Article2">
      <button id="work2BtnCle">AC</button>
      <button id="work2BtnDel">×</button>
      <button id="work2BtnRem">%</button>
      <button id="work2BtnDiv">/</button>
      <button id="work2Btn7">7</button>
      <button id="work2Btn8">8</button>
      <button id="work2Btn9">9</button>
      <button id="work2BtnMul">*</button>
      <button id="work2Btn4">4</button>
      <button id="work2Btn5">5</button>
      <button id="work2Btn6">6</button>
      <button id="work2BtnSub">-</button>
      <button id="work2Btn1">1</button>
      <button id="work2Btn2">2</button>
      <button id="work2Btn3">3</button>
      <button id="work2BtnAdd">+</button>
      <button id="work2BtnNull">未开发</button>
      <button id="work2Btn0">0</button>
      <button id="work2BtnPoi">.</button>
      <button id="work2BtnEqu">=</button>
    </article>
  </section>
    
  <script>
    
    var num = "0";         //输入的原式
    var res = 0 ;          //结果

    var work2Article1 = document.getElementById('work2Article1');

    var work2BtnCle = document.getElementById('work2BtnCle');
    var work2BtnDiv = document.getElementById('work2BtnDiv');
    var work2BtnDel = document.getElementById('work2BtnDel');
    var work2BtnRem = document.getElementById('work2BtnRem');
    var work2BtnMul = document.getElementById('work2BtnMul');
    var work2BtnSub = document.getElementById('work2BtnSub');
    var work2BtnAdd = document.getElementById('work2BtnAdd');
    var work2BtnNull = document.getElementById('work2BtnNull');
    var work2BtnPoi = document.getElementById('work2BtnPoi');
    var work2BtnEqu = document.getElementById('work2BtnEqu');
    
    var work2Btn1 = document.getElementById('work2Btn1');
    var work2Btn2 = document.getElementById('work2Btn2');
    var work2Btn3 = document.getElementById('work2Btn3');
    var work2Btn4 = document.getElementById('work2Btn4');
    var work2Btn5 = document.getElementById('work2Btn5');
    var work2Btn6 = document.getElementById('work2Btn6');
    var work2Btn7 = document.getElementById('work2Btn7');
    var work2Btn8 = document.getElementById('work2Btn8');
    var work2Btn9 = document.getElementById('work2Btn9');
    var work2Btn0 = document.getElementById('work2Btn0');
    
    // 初始化
    work2BtnCle.onclick = function () {
      num = "0" ;
      work2Article1.innerText=`${num}`;
    }
   
    work2BtnDel.onclick = function () {
      // 判断原式长度，长度为1时变为0
      if(num.length==1){
        num = '0' ;
        work2Article1.innerText=num;
        // 否则减去最后一位
      }else{
        num = num.substring(0,num.length-1);
        work2Article1.innerText=num;
      }
    }
    // 运算符点击事件
    work2BtnDiv.onclick = function () {
      num += "/" 
      work2Article1.innerText=num;
    }
    work2BtnRem.onclick = function () {
      num += "%" ; 
      work2Article1.innerText=`${num}`;
    }
    work2BtnMul.onclick = function () {
      num += "*" ; 
      work2Article1.innerText=`${num}`;
    }
    work2BtnAdd.onclick = function () {
      num += "+" ; 
      work2Article1.innerText=`${num}`;
    }
    work2BtnNull.onclick = function () {
      alert('下次一定开发出来');
    }
    work2BtnPoi.onclick = function () {
      num += "." ; 
      work2Article1.innerText=`${num}`;
    }
    work2BtnSub.onclick = function () {
      num += "-" ; 
      work2Article1.innerText=`${num}`;
    }
   
    // 数字点击事件
    work2Btn1.onclick =function(){
      if( num == "0" ){
        num = "1";
      }else{
        num += "1" ;
      }
      work2Article1.innerText=`${num}`;
    }
    work2Btn2.onclick =function(){
      if( num == "0" ){
        num = "2";
      }else{
        num += "2" ;
      }
      work2Article1.innerText=`${num}`;
    }
    work2Btn3.onclick =function(){
      if( num == "0" ){
        num = "3";
      }else{
        num += "3" ;
      }
      work2Article1.innerText=`${num}`;
    }
    work2Btn4.onclick =function(){
      if( num == "0" ){
        num = "4";
      }else{
        num += "4" ;
      }
      work2Article1.innerText=`${num}`;
    }
    work2Btn5.onclick =function(){
      if( num == "0" ){
        num = "5";
      }else{
        num += "5" ;
      }
      work2Article1.innerText=`${num}`;
    }
    work2Btn6.onclick =function(){
      if( num == "0" ){
        num = "6";
      }else{
        num += "6" ;
      }
      work2Article1.innerText=`${num}`;
    }
    work2Btn7.onclick =function(){
      if( num == "0" ){
        num = "7";
      }else{
        num += "7" ;
      }
      work2Article1.innerText=`${num}`;
    }
    work2Btn8.onclick =function(){
      if( num == "0" ){
        num = "8";
      }else{
        num += "8" ;
      }
      work2Article1.innerText=`${num}`;
    }
    work2Btn9.onclick =function(){
      if( num == "0" ){
        num = "9";
      }else{
        num += "9" ;
      }
      work2Article1.innerText=`${num}`;
    }
    work2Btn0.onclick =function(){
      if( num == "0" ){
        num = "0";
      }else{
        num += "0" ;
      }
      work2Article1.innerText=`${num}`;
    }
  
  
    work2BtnEqu.onclick = function () {
      // num = Number(num);


      //检测运算符号的位置 
      function obtainSymbol(){
        var num1 = [];
        var o = 0 ;
        for(var i = 0 ; i<=num.length ; i++){
          if(num.charAt(i)=='+'){
            num1[o] = i ;
            o++;
          }else if(num.charAt(i)=='-'){
            num1[o] = i ;
            o++;
          }else if(num.charAt(i)=='*'){
            num1[o] = i ;
            o++;
          }else if(num.charAt(i)=='/'){
            num1[o] = i ;
            o++;
          }else if(num.charAt(i)=='%'){
            num1[o] = i ;
            o++;
          }
        }
        return num1 ;
      }

      var res1 = 0 ;     //计算结果
      var numStar = num ;  //重新获取原式子
      // 检测乘除取余运算
      var num1 = obtainSymbol();
      console.log(num1);

      // 检测除了第一个符号之外的乘除取余运算
      for( var w = 0 ; w <= num1.length ; w++ ){
        if(w != 0){
          if( num.charAt(num1[w]) == '*' || num.charAt(num1[w]) == '/' || num.charAt(num1[w]) == '%' ){
            if(w != num1.length-1){
              switch(num.charAt(num1[w])){
              case '*': var l =Number(num.substring(num1[w-1],num1[w]))*Number(num.substring(num1[w]+1,num1[w+1])) ;
                  console.log(l);
                  num = num.substring(0,num1[w-1]+1) + l + num.substring(num1[w+1]) ; 
                  break;
              case '/': var l =Number(num.substring(num1[w-1],num1[w]))*Number(num.substring(num1[w]+1,num1[w+1])) ;
                  num = num.substring(0,num1[w-1]+1) + l + num.substring(num1[w+1]) ; break;
              case '%': var l =Number(num.substring(num1[w-1],num1[w]))*Number(num.substring(num1[w]+1,num1[w+1])) ;
                  num = num.substring(0,num1[w-1]+1) + l + num.substring(num1[w+1]) ; break;
              }
            }else if(w == num1.length-1 ){
              switch(num.charAt(num1[w])){
              case '*': var l =Number(num.substring(num1[w-1]+1,num1[w])) * Number(num.substring(num1[w]+1)) ;
                  num = num.substring(0,num1[w-1]+1) + l ;
                  break;
              case '/': var l =Number(num.substring(num1[w-1]+1,num1[w])) / Number(num.substring(num1[w]+1)) ;
                  num = num.substring(0,num1[w-1]+1) + l ; break;
              case '%': var l =Number(num.substring(num1[w-1]+1,num1[w])) % Number(num.substring(num1[w]+1)) ;
                  num = num.substring(0,num1[w-1]+1) + l; break;
              }
            }
          num1 = 0 ;
          num1 = obtainSymbol();
          w -= 1;
          }
        }
      }
      
      // 从第一位运算符开始运算
      for(var k = 0 ; k < num1.length ; k++){
        if(k==0){        
          switch(num.charAt(num1[k])){
            case '+': res1 += Number(num.substring(0,num1[k])) + Number(num.substring(num1[k]+1,num1[k+1])) ; break;
            case '-': res1 += Number(num.substring(0,num1[k])) - Number(num.substring(num1[k]+1,num1[k+1])) ; break;
            case '*': res1 += Number(num.substring(0,num1[k])) * Number(num.substring(num1[k]+1,num1[k+1])) ; break;
            case '/': res1 += Number(num.substring(0,num1[k])) / Number(num.substring(num1[k]+1,num1[k+1])) ; break;
            case '%': res1 += Number(num.substring(0,num1[k])) % Number(num.substring(num1[k]+1,num1[k+1])) ; break; 
          }
        }else{
          switch(num.charAt(num1[k])){
            case '+': 
              if(k==num1.length-1){
              res1 += Number(num.substring(num1[k]+1)) ;
            
              }else{
                res1 += Number(num.substring(num1[k]+1,num1[k+1])); 
              }break;
            case '-': 
              if(k==num1.length-1){
              res1 -= Number(num.substring(num1[k]+1)) ;
              }else{
                res1 -= Number(num.substring(num1[k]+1,num1[k+1])); 
              }break;
            case '*': 
              if(k==num1.length-1){
              res1 *= Number(num.substring(num1[k]+1)) ;
              }else{
                res1 *= Number(num.substring(num1[k]+1,num1[k+1])); 
              }break;
            case '/': 
              if(k==num1.length-1){
              res1 /= Number(num.substring(num1[k]+1)) ;
              }else{
                res1 /= Number(num.substring(num1[k]+1,num1[k+1])); 
              }break;
            case '%': 
              if(k==num1.length-1){
              res1 %= Number(num.substring(num1[k]+1)) ;
              }else{
                res1 %= Number(num.substring(num1[k]+1,num1[k+1])); 
              }break;
          }
          
        } 
      }
  
      work2Article1.innerText=`${numStar}=${res1}`;
    }
  </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。

DDR爱好者之家 Design By 杰米
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稳了！魔兽国服回归的3条重磅消息！官宣时间再确认！

昨天有一位朋友在大神群里分享，自己亚服账号被封号之后居然弹出了国服的封号信息对话框。

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而他在复制这个网址并且进行登录之后，确实是网易的网址，也就是我们熟悉的停服之后国服发布的暴雪游戏产品运营到期开放退款的说明。这是一件比较奇怪的事情，因为以前都没有出现这样的情况，现在突然提示跳转到国服战网的网址，是不是说明了简体中文客户端已经开始进行更新了呢？

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