set&clear interval
by shengoo
HTML
<p>A script on this page starts this clock:</p>
<p id="demo"></p>
<button onclick="myStopFunction()">Stop time</button>
JavaScript
var myVar = setInterval(myTimer,1000);
function myTimer()
{
var d = new Date();
var t = d.toLocaleTimeString();
document.getElementById("demo").innerHTML=t;
}
function myStopFunction()
{
clearInterval(myVar);
}