if (res == 1) {
   document.write("<LINK rel=stylesheet href=\"klanten_css/opo1.css\" type=\"text/css\">"); }
else if (res == 2) {
   document.write("<LINK rel=stylesheet href=\"klanten_css/opo2.css\" type=\"text/css\">"); }
else if (res == 3) {
   document.write("<LINK rel=stylesheet href=\"klanten_css/opo3.css\" type=\"text/css\">"); }
else if (res == 4) {
   document.write("<LINK rel=stylesheet href=\"klanten_css/opo4.css\" type=\"text/css\">"); }
else if (res == 5) {
   document.write("<LINK rel=stylesheet href=\"klanten_css/opo5.css\" type=\"text/css\">"); }