Sokoljr,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<div id="watch"></div>
<button>Start</button>
<button>Reset</button>
<script>
var buttons = document.getElementsByTagName ("button"), timer;
buttons[0].addEventListener("click", goTime);
buttons[1].addEventListener("click", endTime);
function goTime()
{
time();
timer = setInterval(time, 1000);
}
function endTime()
{
window.clearInterval(timer);
//document.getElementById("watch").innerHTML = "00:00:00"
}
function time() {
var d = new Date();
document.getElementById("watch").innerHTML = d.toLocaleTimeString();
}
</script>
</body>
</html>