How can I make a link in one div open to replace another div that's a seperate file?

[Laura Wilkinson]

Hello :),

Basically, I am creating a website and the "frames" I've created are made from divs. I want to make my code, so that when a link in the left column is clicked, a different page, with the same format as the main div appears in it's place. I can include the code I've done (which might be me making it complicated). If you could help, that would be lovely!

Here's the code;

<div id="leftcolumn">
		<h2>
		Links
		</h2>
		<p>
		<ul>
		<il><a onclick="display_area('home.html')">Home</a></il>
		<br /><br />
		<il><a onclick="display_area('XMLPage/xml.html')">XML Page</a></il>
		<br /><br />
		<il><a onclick="display_area('SlideShow/slideshow.html')">Slide Show</a></il>
		<br /><br />
		<il><a onclick="display_area('Calculator/calculator.html')">Calculator</a></il>
		<br /><br />
		<il><a onclick="display_area('OrderForm/order.html')">Order Form</a></il>
		<br /><br />
		<il><a onclick="display_area('MyReport/report.html')">My Report</a></il>
		</ul>
	</div>

	<div id="homearea">
	<div id="homecontent">

	Displayed on initial page load.

	</div>

		<div id="home" style="display:none"><?php include("home.html"); ?></div>
		<div id="xml" style="display:none"><?php include("XMLPage/xml.html"); ?></div>
		<div id="slideshow" style="display:none"><?php include("SlideShow/slideshow.html"); ?></div>
		<div id="calculator" style="display:none"><?php include("Calculator/calculator.html"); ?></div>
		<div id="order" style="display:none"><?php include("OrderForm/order.html"); ?></div>
		<div id="report" style="display:none"><?php include("MyReport/report.html"); ?></div>

	</div>

	<div id="footer">
	</div>

</div>
</body>

	<script type="text/javascript">
	var dLast=document.getElementById('homecontent');
	var dCurrent;
	function display_area(s)
	{
	new_area=document.getElementById('s');
	dLast.style.display="none";
	new_area.style.display="block";
	dLast=new_area;
	}
	</script>

</html>