How to Create a Binary Calculator using HTML, CSS and JavaScript?

Difficulty Level : Medium
Last Updated : 01 Nov, 2020

HTML or HyperText Markup Language along with CSS (Cascading Stylesheet) and JavaScript can be used to develop interactive user applications that can perform certain functionalities. Similarly, a binary calculator can be developed using HTML, CSS, and JS altogether. Binary Calculator performs arithmetic operations on binary numbers. Binary Calculator has a buffer limit of 8 bits. If the result of the arithmetic operation exceeds 8 bits then the extraneous bits are truncated. The arithmetic operations are accomplished using JavaScript functions. The application consists of a display screen where the user input as well as the result of the arithmetic operation is displayed. Two buttons 0 and 1 are used to take input. The + , – , * , / and Calculate buttons are used to perform arithmetic operation on the input. The Calculate button is binded with a JavaScript function calculate(). When the Calculate button is clicked the calculate() function is triggered and the HTML within the ‘output’ division is parsed. The first number and second number are obtained by splitting the string and finally, they are converted into integers using parseInt(). The method parseInt() takes two arguments of which the first is the string to be converted to an integer and the second is the base value which is 2 or binary in this case. Arithmetic operations are performed depending on the addition, subtraction, multiplication, or division operator chosen by the user. The input() function receives the input from the user and displays it to the screen. The backspace() function deletes the last character of the string displayed. The cls() function clears the display screen. The following code snippets implement a binary calculator.

Example: When an input is given by the user, the input remains within the ‘output’ division in the form of HTML. A global variable scr is declared which can be accessed by all the JavaScript functions. When any input is given it is stored in the scr variable. When the Calculate button is clicked the string stored in the scr variable is searched for the presence of an operator using indexOf() method which returns the index of the operator if found else returns -1. If the operator is present the string stored in scr variable is split at the operator symbol (+,-,*,/), and the strings are stored into num array. Since the input is in String format it must be converted to binary integer format to perform the calculations. The strings are parsed using parseint(str,base) method where str is the string to be converted and the base is the base of the number (here binary base = 2). After the binary conversion, the specified arithmetic operation is performed and the result is again stored in scr variable and displayed in the ‘output’ division.

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HTML:

html

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>Binary Calculator</title>
        
        <!--Bootstrap 4 CSS CDN -->
        <link rel="stylesheet" 
              href=
"https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/css/bootstrap.min.css" 
              integrity=
"sha384-TX8t27EcRE3e/ihU7zmQxVncDAy5uIKz4rEkgIXeMed4M0jlfIDPvg6uqKI2xXr2" 
              crossorigin="anonymous" />
    </head>
  
    <body>
        <div class="container">
            <div class="jumbotron">
                <h1>Binary Calculator</h1>
                <div id="output"></div>
                <div class="container mt-2">
                    <div class="row">
                        <div class="col-12">
                            <button type="button" 
                                    class="btn btn-light" 
                                    onclick="input('0')">
                                      0</button>
                            <button type="button" 
                                    class="btn btn-light" 
                                    onclick="input('1')">
                                      1</button>
                            <button type="button" 
                                    class="btn btn-danger float-right ml-2" 
                                    onclick="cls()">
                                      AC</button>
                            <button type="button" 
                                    class="btn btn-warning float-right" 
                                    onclick="backspace()">
                                      Backspace</button>
                        </div>
                    </div>
                    <div class="row mt-2">
                        <div class="col-12">
                            <button type="button" 
                                    class="btn btn-info" 
                                    onclick="input('+')">+</button>
                            <button type="button"
                                    class="btn btn-info" 
                                    onclick="input('-')">-</button>
                            <button type="button" 
                                    class="btn btn-info" 
                                    onclick="input('*')">*</button>
                            <button type="button" 
                                    class="btn btn-info" 
                                    onclick="input('/')">/</button>
                        </div>
                    </div>
                    <div class="row mt-2">
                        <div class="col-12">
                            <button type="button" 
                                    class="btn btn-success" 
                                    onclick="calculate()">Calculate</button>
                        </div>
                    </div>
                </div>
            </div>
        </div>
        <!--jquery and popper.js cdn -->
        <script src=
"https://code.jquery.com/jquery-3.5.1.slim.min.js" 
                integrity=
"sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" 
                crossorigin="anonymous"></script>
        <script src=
"https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/js/bootstrap.bundle.min.js" 
                integrity=
"sha384-ho+j7jyWK8fNQe+A12Hb8AhRq26LrZ/JpcUGGOn+Y7RsweNrtN/tE3MoK7ZeZDyx" 
                crossorigin="anonymous"></script>
    </body>
</html>

CSS:

html

<style type="text/css">
    .jumbotron{
      width : 60%;
      margin : auto;
      text-align: center;
    }
  
    #output{
      border: 2px solid black;
      min-height: 60px;
      text-align: right;
      font-weight: bold;
      font-size: 20px;
    }
  
    .btn{
      min-width: 120px;
      border: 2px solid black;
    }
 </style>

JavaScript:

javascript

<script type="text/javascript">
    var scr = ""; //declared as global v
    function calculate() {
        if (scr.indexOf("+") != -1) {
            // If + is present in the string
            // String obtained from scr is split
            var num = scr.split("+"); 
              
            // The splitted string stores in num array
            var x = parseInt(num[0], 2); 
            
            // The num[0] and num[1] are the two binary 
            // numbers resp
            var y = parseInt(num[1], 2); 
            var sum = x + y;
            var ans = sum.toString(2);
        } else if (scr.indexOf("-") != -1) {
            
            // If - is present in the string
            var num = scr.split("-");
            var x = parseInt(num[0], 2);
            var y = parseInt(num[1], 2);
            var sub = x - y;
            var ans = sub.toString(2);
        } else if (scr.indexOf("*") != -1) {
             
            // If * is present in the string
            var num = scr.split("*");
            var x = parseInt(num[0], 2);
            var y = parseInt(num[1], 2);
            var mul = x * y;
            var ans = mul.toString(2);
        } else if (scr.indexOf("/") != -1) {
            
            // If / is present in the string
            var num = scr.split("/");
            var x = parseInt(num[0], 2);
            var y = parseInt(num[1], 2);
            var div = x / y;
            var ans = div.toString(2);
        }
        scr = ans;
        document.getElementById("output").innerHTML = scr;
  
    function input(ch) {
        scr += ch;
        document.getElementById("output").innerHTML = scr;
  
    function backspace() {
        var b = document.getElementById("output").innerHTML;
        scr = b.substring(0, b.length - 1);
        document.getElementById("output").innerHTML = scr;
  
    function cls() {
        scr = "";
        document.getElementById("output").innerHTML = scr;
    }
</script>

Complete Code:

html

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>Binary Calculator</title>
        
        <!--Bootstrap 4 CSS CDN -->
        <link rel="stylesheet" 
              href=
"https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/css/bootstrap.min.css" 
              integrity=
"sha384-TX8t27EcRE3e/ihU7zmQxVncDAy5uIKz4rEkgIXeMed4M0jlfIDPvg6uqKI2xXr2" 
              crossorigin="anonymous" />
  
        <style type="text/css">
            .jumbotron {
                width: 60%;
                margin: auto;
                text-align: center;
            }
  
            #output {
                border: 2px solid black;
                min-height: 60px;
                text-align: right;
                font-weight: bold;
                font-size: 20px;
            }
  
            .btn {
                min-width: 120px;
                border: 2px solid black;
            }
        </style>
    </head>
  
    <body>
        <div class="container">
            <div class="jumbotron">
                <h1>Binary Calculator</h1>
                <div id="output"></div>
                <div class="container mt-2">
                    <div class="row">
                        <div class="col-12">
                            <button type="button" 
                                    class="btn btn-light" 
                                    onclick="input('0')">0</button>
                            <button type="button" 
                                    class="btn btn-light" 
                                    onclick="input('1')">1</button>
                            <button type="button" 
                                    class="btn btn-danger float-right ml-2" 
                                    onclick="cls()">AC</button>
                            <button type="button" 
                                    class="btn btn-warning float-right" 
                                    onclick="backspace()">Backspace</button>
                        </div>
                    </div>
                    <div class="row mt-2">
                        <div class="col-12">
                            <button type="button" 
                                    class="btn btn-info" 
                                    onclick="input('+')">+</button>
                            <button type="button"
                                    class="btn btn-info" 
                                    onclick="input('-')">-</button>
                            <button type="button" 
                                    class="btn btn-info" 
                                    onclick="input('*')">*</button>
                            <button type="button" 
                                    class="btn btn-info" 
                                    onclick="input('/')">/</button>
                        </div>
                    </div>
                    <div class="row mt-2">
                        <div class="col-12">
                            <button type="button" 
                                    class="btn btn-success" 
                                    onclick="calculate()">Calculate</button>
                        </div>
                    </div>
                </div>
            </div>
        </div>
  
        <script type="text/javascript">
            var scr = ""; //declared as global variable
  
            function calculate() {
                if (scr.indexOf("+") != -1) {
                    // If + is present in the string
                    // String obtained from scr is split
                    var num = scr.split("+"); 
                      
                    // The splitted string stores in num array
                    var x = parseInt(num[0], 2); 
                    
                    // The num[0] and num[1] are the two binary 
                    // numbers resp
                    var y = parseInt(num[1], 2); 
                    var sum = x + y;
                    var ans = sum.toString(2);
                } else if (scr.indexOf("-") != -1) {
                    
                    // If - is present in the string
                    var num = scr.split("-");
                    var x = parseInt(num[0], 2);
                    var y = parseInt(num[1], 2);
                    var sub = x - y;
                    var ans = sub.toString(2);
                } else if (scr.indexOf("*") != -1) {
                     
                    // If * is present in the string
                    var num = scr.split("*");
                    var x = parseInt(num[0], 2);
                    var y = parseInt(num[1], 2);
                    var mul = x * y;
                    var ans = mul.toString(2);
                } else if (scr.indexOf("/") != -1) {
                    
                    // If / is present in the string
                    var num = scr.split("/");
                    var x = parseInt(num[0], 2);
                    var y = parseInt(num[1], 2);
                    var div = x / y;
                    var ans = div.toString(2);
                }
                scr = ans;
                document.getElementById("output").innerHTML = scr;
            }
  
            function input(ch) {
                scr += ch;
                document.getElementById("output").innerHTML = scr;
            }
  
            function backspace() {
                var b = document.getElementById("output").innerHTML;
                scr = b.substring(0, b.length - 1);
                document.getElementById("output").innerHTML = scr;
            }
  
            function cls() {
                scr = "";
                document.getElementById("output").innerHTML = scr;
            }
        </script>
  
        <!--jquery and popper.js cdn -->
        <script src=
"https://code.jquery.com/jquery-3.5.1.slim.min.js" 
                integrity=
"sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" 
                crossorigin="anonymous"></script>
        <script src=
"https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/js/bootstrap.bundle.min.js" 
                integrity=
"sha384-ho+j7jyWK8fNQe+A12Hb8AhRq26LrZ/JpcUGGOn+Y7RsweNrtN/tE3MoK7ZeZDyx" 
                crossorigin="anonymous"></script>
    </body>
</html>

Output

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