הכי פשוט זה עם setInterval
HTML קוד:
<SCRIPT LANGUAGE="JavaScript">
function rand()
{
quotes = new Array(3);
quotes[0] = "sddd";
quotes[1] = "dfdfff";
quotes[2] = "gggg";
index = Math.floor(Math.random() * quotes.length);
document.getElementById('a').innerHTML = quotes[index];
}
setInterval("rand()", 1000);
</SCRIPT>
<div id="a"></div>