script.js

        // login button event handler
        const loginBtn = document.getElementById("login");
        loginBtn.addEventListener("click", function(){
            const loginArea = document.getElementById("login-area");
            loginArea.style.display = "none";
            const transactionArea = document.getElementById("transaction-area");
            transactionArea.style.display = "block";
        })

        //deposit button event handler
        const depositBtn = document.getElementById("addDeposit");
        depositBtn.addEventListener("click", function(){
            const depositNumber = getInputNumber("depositAmount");        

            updateSpanText("currentDeposit", depositNumber);
            updateSpanText("currentBalance", depositNumber);

            document.getElementById("depositAmount").value = "";
        })

        // withdraw button event handler
        const withdrawBtn = document.getElementById("addWithdraw");
        withdrawBtn.addEventListener("click", function(){
            const withdrawNumber = getInputNumber("withdrawAmount");
            
            updateSpanText("currentWithdraw", withdrawNumber);
            updateSpanText("currentBalance", -1 * withdrawNumber);

            document.getElementById("withdrawAmount").value = ""
        })

        function getInputNumber(id){
            const amount = document.getElementById(id).value;
            const amountNumber = parseFloat(amount);
            return amountNumber;
        }

        function updateSpanText(id, addedNumber){
            const current = document.getElementById(id).innerText;
            const currentNumber = parseFloat(current);
            const totalAmount = addedNumber + currentNumber;
            document.getElementById(id).innerText = totalAmount;
        }