function new_window(url) {

link = window.open(url,"Link","toolbar=0,location=0,directories=0,status=0,menubar=no,scrollbars=no,resizable=yes,width=620,height=420,left=0,top=0");

}

function onTop() {
  if (link.blur) link.focus();
}

function button(img_name,img_src) {
document[img_name].src=img_src;
}