var today = new Date();
switch(today.getUTCDate()%3) {
case 1 :
currentimage='header_5_med.jpg'
break;
case 2 :
currentimage='header_8_med.jpg'
break;
default :
currentimage='header_9_med.jpg'
break;
}

function headimage(){
document.write('<p id="mainimg">');
document.write('<img src="/e/products/device/common/img/' + currentimage + '" width="446" height="80" alt="">');
document.write('</p>');
}