var img1 = '1';
var img2 = '3';
var img3 = '7';
var img4 = '9';
var randomize = Math.round(Math.random()*4);
if (randomize == 1){
newimg = img1
}else if (randomize == 2){
newimg = img2
}else if (randomize ==3){
newimg = img3
}else {
newimg = img4
}
document.write('<BODY BACKGROUND=X-labs-BG1-75p-L' + newimg + '.jpg>')