var randomnumber = Math.round(Math.random()*4);
var version = 0;
if (navigator.userAgent.indexOf("Mozilla/4.0") != -1) version = "oit";

if (randomnumber == 1){
document.write('<img src="masthead1.jpg" width=900 height=201>');
}

else if (randomnumber == 2){
document.write('<img src="masthead2.jpg" width=900 height=201>');
}

else if (randomnumber == 3){
document.write('<img src="masthead3.jpg" width=900 height=201>');
}

else {
document.write('<img src="masthead4.jpg" width=900 height=201>');
}