function Header() {
var imgnum = 13;

var myDate=new Date();
myDate.setFullYear(2008,1,11);
var today = new Date();
var timesec = 86400000;
var difference = ((today-myDate)-((today-myDate)%timesec))/timesec;
var filenum = difference % imgnum + 1;


document.write("<table width=100% height=150px background=headers/" + filenum + ".jpg>");
document.write("<tr><td valign=center>");
document.write("<center>");

if (filenum < 6) {
  document.write("<font class=PageTitle1>Poeppelmeier Group</font><br>");
  document.write("<font class=PageSubTitle1>");
}
else if ( (filenum > 5 && filenum < 11)  || filenum > imgnum) {
  document.write("<font class=PageTitle2>Poeppelmeier Group</font><br>");
  document.write("<font class=PageSubTitle2>");
}
else if (filenum > 10) {
  document.write("<font class=PageTitle3>Poeppelmeier Group</font><br>");
  document.write("<font class=PageSubTitle3>");
}
document.write("Inorganic &amp; Solid State Chemistry Research Group</font>");

}