Write a JavaScript Program to Make a Simple Calculator

write-a-javascript-program-to-make-a-simple-calculator

As a JavaScript programmer, creating a simple calculator using JavaScript is a fun and easy project to undertake.

This program will allow you to perform basic arithmetic operations like addition, subtraction, multiplication, and division.

Here’s how to write a simple calculator using JavaScript:

Step 1: Create the HTML Markup

To create a calculator, you’ll first need to create the HTML markup. Here’s an example of what your HTML markup could look like:In this markup, we have created an HTML form that allows the user to enter two numbers and choose an operation to perform using buttons.

<!DOCTYPE html>
<html>
<head>
	<title>JavaScript Calculator</title>
</head>
<body>
	<h1>Calculator</h1>
	<input type="text" id="firstNumber" placeholder="Enter first number">
	<input type="text" id="secondNumber" placeholder="Enter second number">
	<button onclick="add()">+</button>
	<button onclick="subtract()">-</button>
	<button onclick="multiply()">*</button>
	<button onclick="divide()">/</button>
	<p id="result"></p>
	<script src="calculator.js"></script>
</body>
</html>

Step 2: Write the JavaScript Code

Once you have the HTML markup, you can add the JavaScript code that will perform the calculations. Here’s an example of what your JavaScript code could look like:

function add() {
	var firstNumber = parseFloat(document.getElementById("firstNumber").value);
	var secondNumber = parseFloat(document.getElementById("secondNumber").value);
	var result = firstNumber + secondNumber;
	document.getElementById("result").innerHTML = result;
}

function subtract() {
	var firstNumber = parseFloat(document.getElementById("firstNumber").value);
	var secondNumber = parseFloat(document.getElementById("secondNumber").value);
	var result = firstNumber - secondNumber;
	document.getElementById("result").innerHTML = result;
}

function multiply() {
	var firstNumber = parseFloat(document.getElementById("firstNumber").value);
	var secondNumber = parseFloat(document.getElementById("secondNumber").value);
	var result = firstNumber * secondNumber;
	document.getElementById("result").innerHTML = result;
}

function divide() {
	var firstNumber = parseFloat(document.getElementById("firstNumber").value);
	var secondNumber = parseFloat(document.getElementById("secondNumber").value);
	var result = firstNumber / secondNumber;
	document.getElementById("result").innerHTML = result;
}

In this code, we have defined four functions: add(), subtract(), multiply(), and divide(). Each function retrieves the values of the two input fields, performs the appropriate calculation, and displays the result in the paragraph element with the id “result”.

Step 3: Test Your Calculator

Now that you have your HTML markup and JavaScript code, you can test your calculator by opening the HTML file in a web browser.

Enter two numbers, choose an operation, and click the appropriate button. The result of the calculation should appear in the paragraph element with the id “result”.

In conclusion, creating a simple calculator using JavaScript is an easy project that can be accomplished quickly by following the steps outlined above.

With a little bit of HTML and JavaScript knowledge, you can create a fully functional calculator that can perform basic arithmetic operations.

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