JSFiddle - React, Tailwind, and code Playground

HTML

<span data-bind="text: TimeString">Start...</span>

JavaScript

var vm = {
            TimeDT: ko.observable(),
            TimeString: ko.observable()
        };
        
        function updateValues() {
            var data = new Date();
            vm.TimeDT(data);
            vm.TimeString(data);
        }
       
        ko.applyBindings(vm);
    
        updateValues();
        setInterval(updateValues, 5000);