Вот код:
Code
<html>
<head>
<script language="JavaScript">
<!--
function StartStop() {
if (document.getElementById('myScroll').scrollAmount) document.getElementById('myScroll').scrollAmount=0;
else document.getElementById('myScroll').scrollAmount=6;
}
//-->
</script>
</head>
<body>
<marquee id="MyScroll" scrollAmount="6">Текст для прокрутки</marquee>
<form>
<input type="button" onclick="StartStop()" value="Start/Stop">
</form>
</body>
</html>