Building a Simple Calculator Using JavaScript: A Beginner’s Guide

Creating the Calculator Interface

Now that we’ve completed the HTML structure and styled it with CSS, let’s add JavaScript functionality to bring the project to life much like how Big Data vs Data Science compares the foundation and functionality of data-driven technologies.

• The main functionalities of the calculator will include:
• Appending numbers to the display when a number is clicked.
• Setting operations like addition, subtraction, multiplication, and division.
• Calculating the result when the equals button is clicked.
• Clearing the display when clicking the” “” “b” “”” on.



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Adding the JavaScript Functionality

Handling Button Clicks

We will define functions to handle the button clicks. Let’s do this by appendLet’s Letting numbers to the display.

• let current input = ”;
• Store the current input string
• let previous input = “;
• Sto” the previous input (used for operations)
• let current operation = ”;
• Store the current operation
• Append number to the display
• function appendNumber(number) {
• current input += number;
• Add number to the current input
• document.getElementById(‘display’).value = current input;
• Update display
• }

Implementing Basic Operations

Next, we will implement the functionality for setting the operations (addition, subtraction, multiplication, and division).

• Set the operation (addition, subtraction, etc.)
• function separation(operator) {
• if (cif (cif (cif (current input ===”) return;
• Prevent operation if there’s no number (previous input !==”) {put ===”) result();
• If there is existing input,
• catherthere’sexistinglculate before setting a new operation
• }
• current operation = operator;
• Store the current operation
• previous input = current input;
• Store the previous input for the operation
• current input = “; “Rese” cu “ent input for next number
• }

Calculating the Result

Now, we’ll implement the calculateResult function, which performs the actual calculations based on the selected operation demonstrating logical thinking and coding skills essential for exploring Python Career Opportunities.

• Calculate the result based on the operation
• function calculateResult() {
• if (previous (previous input if (previous input === ” || current input === ”) return;
• Prevent calculation if there’s no input current input result;
• previous input === ” ||put === ”) rent input result;previous input current input result
• current operation) {
• case ‘+’:
• result = parseFloat(previous input) + parseFloat(current input);
• break;
• case ‘-‘:’ ‘result = parseFloat(previous input) – parseFloat(current input);
• break;
• case ‘*’:
• result = parseFloat(previous input) * parseFloat(current input);
• break;
• case case ‘result = parseFloat(previous input) / parseFloat(current input);
• break;
• default:
• return;
• }
• document.getElementById(‘display’).value = result;
• Display the result
• previousInput = result.toString();
• Set the result as the previous input for further calculations
• current input = “;
• Res” current input
• }

Clearing the Display

Finally, we will add a function to clear the display when the “C,” “u, “ton,” i,” and “r “are used.

• Clear the display and reset the calculator
• function clearDisplay() {
• current input = ”;
• previous input = ”;
• current operation = ”;
• document.getElementById(‘display’).value = ”;
• }

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Testing and Debugging the Calculator

After implementing all the necessary functions for your calculator, it’s time to test how well it works. Start by opening the HTML file in your preferred web browser. Begin by pressing the number buttons to ensure they correctly appear on the calculator’s display. Next, select one of the basic operations addition, subtraction, multiplication, or division and make sure it registers the input. Press the equals (=) button to calculate the result and confirm that the correct value is displayed. You should also test the clear (C) button to verify that it resets the calculator’s display properly. Try out different combinations of inputs, including edge cases like dividing by zero or entering multiple operations without pressing equals practicing debugging and logic handling, which are among the Top Reasons To Learn Python. If something doesn’t work as expected, open the browser’s developer console (usually with F12 or right-click > Inspect > Console tab) and look for any error messages. These can help you identify and fix problems in your JavaScript code. Testing thoroughly ensures a smooth and reliable user experience.




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Conclusion

You’ve built a simple calculator using JavaScript, and in doing so, you’ve taken an important step in your web development journey. This project introduced you to essential JavaScript concepts such as event handling, functions, and performing basic arithmetic operations. Alongside the JavaScript logic, you also learned how to create a clean and functional user interface using HTML and enhance its appearance with CSS. These skills form the foundation of interactive web development. This tutorial not only helped you understand how to structure a project but also how to bring static content to life with interactivity an approach often emphasized in Data Science Training to create dynamic and engaging user experiences. It’s a great starting point for anyone new to web development. Now that you’ve completed the basic version, you can challenge yourself by adding more advanced features like decimal support, keyboard input handling, memory functions, or even scientific operations. By following this tutorial, you’ve gained valuable hands-on experience in combining HTML, CSS, and JavaScript to build a real, working web application that can be used and expanded further.