var allCookies = document.cookie.split("; "); //in case you have more than one cookie on your site
var skin = ""
for (i=0; i < allCookies.length; i++) {
   crumb = allCookies[i].split("="); 
   if (crumb[0] == "skin") { // find the cookie called skin
     skin = crumb[1]; // assign it's value to a variable
   }
   if (skin == "") {
     skin = "default"
   }
}
// call the correct CSS document
document.write ("<link rel=\"stylesheet\" type=\"text/css\" href=\"http://kirsten-henningsen.dk/forum/css/" + skin + ".css\" id=\"skin\" />")