Add info to div without rewriting HTML

Add info to div without rewriting HTML

Hey,
 
I'm working on www.acars-netherlands.com. We do every 5 seconds an Asynchronious XML-HTTPRequest. The result of this request is displayed in the div messages.
The newest results must be displayed at the top of the page.
The code that we now have is:
var oldmessages = $("#messages").html();
$("#messages").html(ajaxreply + oldmessages);

If we use this, JQuery is rewriting the HTML into the div and a new request to the images is made. Otherwise if we use .before(), the messages are written outside the div messages.
 
Is there a solution to write the ajaxresponse at the top of the div and after the ajaxresponse the old data without rewriting the HTML?
 
Thanks in advance for your reply,
PH_MJS