Have you ever wondered how to build a powerful scientific calculator using JavaScript? Well, you’re in luck! In this step-by-step guide, we’ll walk you through the process of creating your very own JavaScript Scientific Calculator. With a few lines of code and some basic HTML and CSS, you’ll have a functional calculator that can perform a wide range of mathematical operations.
HTML Scientific Calculator Interface
This code creates the user interface for a basic scientific calculator using HTML, featuring a display input field and buttons for numerical input, mathematical operations, and functions. JavaScript functions linked to the buttons handle user interactions and calculations. Note that there are minor issues in the code, such as typographical errors and the deprecated “language” attribute in the script tag, which should be replaced with “type.”
<head>
<script language="javascript"></script>
</head>
<form name="sci-calc">
<table class="calculator" cellspacing="0" cellpadding="1">
<tr>
<td colspan="5"><input id="display" name="display" value="0" size="28" maxlength="25"></td>
</tr>
<tr>
<td><input type="button" class="btnTop" name="btnTop" value="C" onclick="this.form.display.value= 0 "></td>
<td><input type="button" class="btnTop" name="btnTop" value="<--" onclick="deleteChar(this.form.display)"></td>
<td><input type="button" class="btnTop" name="btnTop" value="=" onclick="if(checkNum(this.form.display.value)) { compute(this.form) }"></td>
<td><input type="button" class="btnOpps" name="btnOpps" value="π" onclick="addChar(this.form.display,'3.14159265359')"></td>
<td><input type="button" class="btnMath" name="btnMath" value="%" onclick=" percent(this.form.display)"></td>
</tr>
<tr>
<td><input type="button" class="btnNum" name="btnNum" value="7" onclick="addChar(this.form.display, '7')"></td>
<td><input type="button" class="btnNum" name="btnNum" value="8" onclick="addChar(this.form.display, '8')"></td>
<td><input type="button" class="btnNum" name="btnNum" value="9" onclick="addChar(this.form.display, '9')"></td>
<td><input type="button" class="btnOpps" name="btnOpps" value="x^" onclick="if(checkNum(this.form.display.value)) { exp(this.form) }"></td>
<td><input type="button" class="btnMath" name="btnMath" value="/" onclick="addChar(this.form.display, '/')"></td>
<tr>
<td><input type="button" class="btnNum" name="btnNum" value="4" onclick="addChar(this.form.display, '4')"></td>
<td><input type="button" class="btnNum" name="btnNum" value="5" onclick="addChar(this.form.display, '5')"></td>
<td><input type="button" class="btnNum" name="btnNum" value="6" onclick="addChar(this.form.display, '6')"></td>
<td><input type="button" class="btnOpps" name="btnOpps" value="ln" onclick="if(checkNum(this.form.display.value)) { ln(this.form) }"></td>
<td><input type="button" class="btnMath" name="btnMath" value="*" onclick="addChar(this.form.display, '*')"></td>
</tr>
<tr>
<td><input type="button" class="btnNum" name="btnNum" value="1" onclick="addChar(this.form.display, '1')"></td>
<td><input type="button" class="btnNum" name="btnNum" value="2" onclick="addChar(this.form.display, '2')"></td>
<td><input type="button" class="btnNum" name="btnNum" value="3" onclick="addChar(this.form.display, '3')"></td>
<td><input type="button" class="btnOpps" name="btnOpps" value="√" onclick="if(checkNum(this.form.display.value)) { sqrt(this.form) }"></td>
<td><input type="button" class="btnMath" name="btnMath" value="-" onclick="addChar(this.form.display, '-')"></td>
</tr>
<tr>
<td><input type="button" class="btnMath" name="btnMath" value="±" onclick="changeSign(this.form.display)"></td>
<td><input type="button" class="btnNum" name="btnNum" value="0" onclick="addChar(this.form.display, '0')"></td>
<td><input type="button" class="btnMath" name="btnMath" value="." onclick="addChar(this.form.display, '.')"></td>
<td><input type="button" class="btnOpps" name="btnOpps" value="x2" onclick="if(checkNum(this.form.display.value)) { square(this.form) }"></td>
<td><input type="button" class="btnMath" name="btnMath" value="+" onclick="addChar(this.form.display, '+')"></td>
</tr>
<tr>
<td><input type="button" class="btnMath" name="btnMath" value="(" onclick="addChar(this.form.display, '(')"></td>
<td><input type="button" class="btnMath" name="btnMath" value=")" onclick="addChar(this.form.display,')')"></td>
<td><input type="button" class="btnMath" name="btnMath" value="cos" onclick="if(checkNum(this.form.display.value)) { cos(this.form) }"></td>
<td><input type="button" class="btnMath" name="btnMath" value="sin" onclick="if(checkNum(this.form.display.value)) { sin(this.form) }"></td>
<td><input type="button" class="btnMath" name="btnMath" value="tan" onclick="if(checkNum(this.form.display.value)) { tan(this.form) }"></td>
</tr>
</tabel>
</form>CSS Styling for a Scientific Calculator:
In this CSS code, styles are defined for a scientific calculator’s visual elements. It sets the layout, colors, borders, and sizes for the calculator’s components, including the display, buttons for digits, mathematical operations, and functions. The code ensures a visually appealing and user-friendly calculator interface.
* {
padding: 0;
margin: 5px;
text-align: center;
}
body {
background-color:grey;
}
.calculator {
width: 350px;
height: 320px;
background-color: #c0c0c0;
box-shadow: 0px 0px 0px 10px #666;
border: 5px solid black;
border-radius: 10px;
}
#display {
width: 320px;
height: 40px;
text-align: right;
background-color: black;
border: 3px solid grey;
font-size: 18px;
left: 2px;
top: 2px;
color: #e60f0f;
}
.btnTop{
color: white;
background-color: #6f6f6f;
font-size: 14px;
margin: auto;
width: 50px;
height: 25px;
}
.btnNum {
color: white;
background-color: #00000082;
font-size: 14px;
margin: auto;
width: 50px;
height: 25px;
}
.btnMath {
color: white;
background-color: #d90d0dd1;
font-size: 14px;
margin: auto;
width: 50px;
height: 25px;
}
.btnOpps {
color: white;
background-color: #d90d0dd1;
font-size: 14px;
margin: auto;
width: 50px;
height: 25px;
}JavaScript Scientific Calculator Functions:
This code contains JavaScript functions for a scientific calculator. These functions handle character input, trigonometric and mathematical calculations (e.g., cos, sin, sqrt), basic operations (delete, sign change, percentage), and expression evaluation while validating input.
function addChar(input, character) {
if(input.value == null || input.value == "0")
input.value = character
else
input.value += character
}
function cos(form) {
form.display.value = Math.cos(form.display.value);
}
function sin(form) {
form.display.value = Math.sin(form.display.value);
}
function tan(form) {
form.display.value = Math.tan(form.display.value);
}
function sqrt(form) {
form.display.value = Math.sqrt(form.display.value);
}
function ln(form) {
form.display.value = Math.log(form.display.value);
}
function exp(form) {
form.display.value = Math.exp(form.display.value);
}
function deleteChar(input) {
input.value = input.value.substring(0, input.value.length - 1)
}
var val = 0.0;
function percent(input) {
val = input.value;
input.value = input.value + "%";
}
function changeSign(input) {
if(input.value.substring(0, 1) == "-")
input.value = input.value.substring(1, input.value.length)
else
input.value = "-" + input.value
}
function compute(form) {
//if (val !== 0.0) {
// var percent = form.display.value;
// percent = pcent.substring(percent.indexOf("%")+1);
// form.display.value = parseFloat(percent)/100 * val;
//val = 0.0;
// } else
form.display.value = eval(form.display.value);
}
function square(form) {
form.display.value = eval(form.display.value) * eval(form.display.value)
}
function checkNum(str) {
for (var i = 0; i < str.length; i++) {
var ch = str.charAt(i);
if (ch < "0" || ch > "9") {
if (ch != "/" && ch != "*" && ch != "+" && ch != "-" && ch != "."
&& ch != "(" && ch!= ")" && ch != "%") {
alert("invalid entry!")
return false
}
}
}
return true
}Scientific Calculator In Javascript Demo
You’ve just created a basic JavaScript Scientific Calculator. You can further enhance it by adding more mathematical functions, styling it with CSS, and ensuring it handles edge cases gracefully. Building a calculator is a great way to practice your JavaScript skills and create a useful tool for yourself or others.
