calculate time

                <div class="spec grid">
                    <div class="city" id="brussels"></div>
                    <div class="city" id="london"></div>
                    <div class="city" id="tokyo"></div>
                    <div class="city" id="new_york"></div>
                    <div class="city" id="arizona"></div>
                </div>
                <style>
                    .city{position: relative; background-color: lightgrey; color: blue; width: 20vw; 
                        height: 2vw; font-size: 1vw; padding: 1vw; border: 0.2vw solid skyblue;}
                </style>
                <script>
                    function calculateDateTime(offset) {
                        var date = new Date();
                        var localTime = date.getTime();
                        var localOffset = date.getTimezoneOffset() * 60000;
                        var utc = localTime + localOffset;
                        var newDateTime = utc + (3600000 * offset);
                        var convertedDateTime = new Date(newDateTime);
                        return convertedDateTime.toLocaleString();
                    }
                    document.getElementById("brussels").innerHTML = "Brussels - time: " + (calculateDateTime(1));
                    document.getElementById("london").innerHTML = "London - time: " + (calculateDateTime(0));
                    document.getElementById("tokyo").innerHTML = "Tokyo - time: " + (calculateDateTime(9));
                    document.getElementById("new_york").innerHTML = "New York - time: " + (calculateDateTime(-5));
                    document.getElementById("arizona").innerHTML = "Arizona - time: " + (calculateDateTime(-7));
                </script>