<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>abort action</title>
</head>
<body>
<div>
<p id="p1">0</p>
<input id="but1" type="button" value="остановить счётчик"/>
</div>
<script type="text/javascript">
var a = 1;
function getPOST() {
document.getElementById("p1").innerHTML = a++;
}
var aaa = setInterval(getPOST, 1000);
document.getElementById("but1").onclick = function () {
clearInterval(aaa);
alert("Всё работает! Не надо ля-ля!!!");
}
</script>
</body>
</html>