[iframe] An Iframe I need to refresh every 30 seconds (but not the whole page)

I have this bit of code

<iframe marginwidth="0" marginheight="0" width="240" height="80" scrolling="no" frameborder=0 src="irc_online.php">
</iframe>

I am adding this to a html widget I have on a sidebar, Is there a way I can make this refresh say every 30 seconds and not the rest of my page?

Okay... so i know that i'm answering to a decade question, but wanted to add something! I wanted to add a google calendar with special iframe parameters. Problem is that the calendar didn't work without it. 30 seconds is a bit short for my use, so i changed that in my own file to 15 minutes This worked for me.

<script>
window.setInterval("reloadIFrame();", 30000);
function reloadIFrame() {
 document.getElementById("calendar").src=calendar.src;
}
</script>

    <iframe id="calendar" src="[URL]" style="border-width:0" width=100% height=100% frameborder="0" scrolling="no"></iframe>

I have a simpler solution. In your destination page (irc_online.php) add an auto-refresh tag in the header.

add "id='myiframe'" to the iframe, then use this script :

<script>

function f1()
{
 var x=document.getElementById("myiframe");
   x.src=x.src+Math.floor(random()%100000);
}

setInterval(f1,30*1000);

</script>

Let's assume that your iframe id= myIframe

here is the code:

<script>
window.setInterval("reloadIFrame();", 30000);
function reloadIFrame() {
 document.getElementById("myIframe").src="YOUR_PAGE_URL_HERE";
}
</script>