function popup580x600(datei) {
var b =580;
var h = 600;
var x = screen.width/2 - b/2;
var y = screen.height/2 - h/2;
fenster = window.open(datei, "_blank", "width="+b+", height="+h+", left="+x+", top="+y+", scrollbars=yes, resizable=no");
}