Building a Web Calculator .. I wanted to build something that looked simple at first but would let me practice writing clean JavaScript and handling user interactions. A calculator felt like the perfect project because there’s more going on behind the scenes than it seems.I started with the basic layout using HTML and CSS, making sure it was responsive so it would work well on both desktop and mobile screens. After that, I focused on getting the core calculations working. Basic operations were straightforward, but adding scientific functions like factorial, square root, logarithm, powers, and modulus required more input processing before evaluating expressions.One of the challenges I ran into was handling invalid expressions. Users don’t always type perfectly, so I added input validation and automatically closed missing parentheses to reduce errors. I also made sure the calculator displayed a friendly error message instead of crashing whenever an invalid calculation occurred.The feature I enjoyed the most was keyboard navigation. Instead of limiting the calculator to mouse clicks, I added support for navigating between buttons with the arrow keys and activating them from the keyboard. It made the application feel much closer to using a real calculator.To make the experience more interactive, I also added sound effects for button presses, calculations, deleting characters, and errors. They’re small details, but they make the interface feel more responsive and satisfying to use.Overall, this project helped me get more comfortable with DOM manipulation, keyboard events, regular expressions, input validation, and building interactive interfaces using plain JavaScript without relying on any frameworks. It was a fun reminder that even a simple application can involve a lot of interesting problem-solving.