if (res == 1) {
   document.write("<LINK rel=stylesheet href=\"klanten_css/gvb1.css\" type=\"text/css\">"); }
else if (res == 2) {
   document.write("<LINK rel=stylesheet href=\"klanten_css/gvb2.css\" type=\"text/css\">"); }
else if (res == 3) {
   document.write("<LINK rel=stylesheet href=\"klanten_css/gvb3.css\" type=\"text/css\">"); }
else if (res == 4) {
   document.write("<LINK rel=stylesheet href=\"klanten_css/gvb4.css\" type=\"text/css\">"); }
else if (res == 5) {
   document.write("<LINK rel=stylesheet href=\"klanten_css/gvb5.css\" type=\"text/css\">"); }