script.js

let string = "";
let button = document.querySelectorAll(".num");
// let star;
// function back() {
// 	var value = document.getElementById("d").value;
// 	document.getElementById("d").value = value.substr(0, value.length - 1);
// }
// const back = () => {
// 	let value = document.getElementById("d");
// };
Array.from(button).forEach((button) => {
	button.addEventListener("click", (e) => {
		if (e.target.innerHTML == "=") {
			string = eval(string.replace("X", "*"));

			document.querySelector("input").value = string;
		} else if (e.target.innerHTML == "C") {
			string = " ";
			document.querySelector("input").value = string;
		} else if (e.target.innerHTML == "d") {
			string = string.slice(0, -1);
			// string = "";
			document.querySelector("input").value = string;
		} else {
			console.log(e.target);
			string = string + e.target.innerHTML;
			document.querySelector("input").value = string;
		}
	});
});