JSFiddle - React, Tailwind, and code Playground

HTML

<body>
<div id='timer'>
		<button class='playerButtons' id='playT' type='submit' onclick='cd()'>Play</button>
		<button class='playerButtons' id='pauseT' type='submit' onclick='pause()'>Pause</button>
		<button class='playerButtons' id='stopT' type='submit' onclick='stop()'></button>
<div id='cdtime'></div>
</div>
</body>

JavaScript

var minutesleft = 60;
var secondsleft = 0;
var millisecondsleft = 0;
var bool = true;
var paused = false;
var end;
var now;

function pause(){
    paused = true;
}

function stop(){
    end = now;
    bool = true;
}

document.getElementById("cdtime").innerHTML = minutesleft + ":" + secondsleft + "0:" + millisecondsleft + "0";
function cd(){
    if (bool) {
        end = new Date();
        end.setMinutes(end.getMinutes()+minutesleft);
        end.setSeconds(end.getSeconds()+secondsleft);
        end.setMilliseconds(end.getMilliseconds()+millisecondsleft);
        bool = false;
    }
    now = new Date();
    diff = end - now;
    diff = new Date(diff);
    var msec = diff.getMilliseconds();
    var sec = diff.getSeconds();
    var min = diff.getMinutes();
    if (min < 10){
        min = "0" + min;
    }
    if (sec < 10){
        sec = "0" + sec;
    }
    if(msec < 10){
        msec = "00" +msec;
    }
    else if(msec < 100){
        msec = "0" +msec;
    }
    if(now >= end){
        clearTimeout(timerID);
        document.getElementById("cdtime").innerHTML = 'POLICE IS HERE';
    }
    else{
    document.getElementById("cdtime").innerHTML = min + ":" + sec + ":" + msec;
    }
    if (paused == false){
        timerID = setTimeout("cd()", 10);
    }
    else {
        bool = true;
        minutesleft = min;
        secondsleft = sec;
        millisecondsleft = msec;
    }
    paused = false;
}