var randnum = Math.random();
var inum = 11;
var rand1 = Math.round(randnum * (inum-1)) + 1;
imgs = new Array
imgs[1] = "img/header1.jpg"
imgs[2] = "img/header2.jpg"
imgs[3] = "img/header3.jpg"
imgs[4] = "img/header4.jpg"
imgs[5] = "img/header5.jpg"
imgs[6] = "img/header6.jpg"
imgs[7] = "img/header7.jpg"
imgs[8] = "img/header8.jpg"
imgs[9] = "img/header9.jpg"
imgs[10] = "img/header10.jpg"
imgs[11] = "img/header11.jpg"
imgs[12] = "img/header12.jpg"
var img = imgs[rand1]