Load script only for returning USER!

I need a script which will load another script only for returning user!

The script which will need to load this script:

<a href="http://www.w3.org/" >W3C</a>

I have a script which loads a popup only for new customers:

<!-- Script courtesy of http://www.web-source.net - Your Guide to Professional Web Site Design and Development
function GetCookie(name) {
var arg=name+"=";
var alen=arg.length;
var clen=document.cookie.length;
var i=0;
while (i<clen) {
var j=i+alen;
if (document.cookie.substring(i,j)==arg)
return "here";
i=document.cookie.indexOf(" ",i)+1;
if (i==0) break;
return null;
var visit=GetCookie("COOKIE1");
if (visit==null){
var expire=new Date();
window.name = "thiswin";
newwin=open("yourpagename.html", "dispwin", 
expire=new Date(expire.getTime()+7776000000);
document.cookie="COOKIE1=here; expires="+expire;
// -->



Yet I need the script only to load once for the returning customers every 1 day

thanks again