var n = new Array("../imgs/header-img-1.jpg","../imgs/header-img-2.jpg","../imgs/header-img-3.jpg","../imgs/header-img-4.jpg","../imgs/header-img-5.jpg","../imgs/header-img-6.jpg");
var r = Math.floor(Math.random()*n.length);
document.write('<img src="'+n[r]+'">');