function loading(){

document.writeln("<div style='position:absolute; width:400px; height:200px; top:10px; left:10px; z-index:1; visibility:hidden' id='DIVI'><table style='height:200px;border:1px solid #ffffff' cellpadding='0' cellspacing='0' width='400' id='table1'><tr><td><CeNTER><img src='_images/loader.gif'><BR><BR><font color='#c4c4c4' face='verdana' size='1'><blink>BITTE WARTEN</blink></font></center></tr></table></div>");

var height;
var width;

height = screen.height / 2;
height = height - 220;
height = ""+height+"px";

width  = screen.width / 2;
width  = width - 220;
width  = ""+width+"px";

document.getElementById('DIVI').style.visibility = "visible";
document.getElementById('DIVI').style.top  = height;
document.getElementById('DIVI').style.left = width;
}

loading();

function fertig(){
document.getElementById('DIVI').style.visibility = "hidden";
}