var banner= new Array()
banner[0]="http://kazasou.files.wordpress.com/2010/03/black-rock-shooter11.jpg"
banner[1]="http://i41.tinypic.com/qs1o95.png"
banner[2]="http://i43.tinypic.com/x6d1zs.png"
banner[3]="http://i42.tinypic.com/30hwvmp.png"
var random=Math.floor(4*Math.random());
document.write("<style>");
document.write("body {");
document.write(' background:url("' + banner[random] + '") no-repeat center center;background-attachment:fixed;');
document.write(" }");
document.write("</style>");