posting ads under iframe - how to prevent overlapp?

I need to post ads under the iframe. But the iframe changes height as you navigate and it creates overlapping with the ads. How do you fix it?

			#[COLOR="Red"][B]ifrindexdiv[/B][/COLOR] {
				position: absolute;
				left: 0px;
				top: 0px;
				<%'text-align: center;%>
				margin: auto;
				border: 0px;
			}
			#[COLOR="Magenta"][B]ifrindex[/B][/COLOR] {
				position: relative;
				left: 0px;
				top: 0px;
				width: 875px;
				height: 1800px;
				scrolling: none;
				<%'border: double 2px #553C1D;%>
			}


							<div id="[COLOR="Red"][B]ifrindexdiv[/B][/COLOR]">
								<iframe name="ifrindex" id="[COLOR="Magenta"][B]ifrindex[/B][/COLOR]" allowtransparency="false" src="forums/index.php" frameborder="0" scrolling="no"></iframe>
							</div>

Code (markup):

 

Can you not use

overflow:hidden;

 

No. I think that has to do with taking out the scrolling. But I tried and it resizes the iframe anyways.

Could it be position? How about if I put position relative instead of absolute?

 

Ok What I did was to place the advertisement in the same div tag as the iframe. But the problem now is that since the iframe is long in height to make some of the pages to fit there are other times when it's short and the ad would remain way at the bottom.

Is it possible to shrink the iframe when it doesn't need to be long in height?