var n=rand(4);
if(n==0){
document.getElementById("container").style.backgroundImage="url(09fs/images/bg/2.jpg)";
}
else if (n==1){
document.getElementById("container").style.backgroundImage="url(09fs/images/bg/1.jpg)";
}else if (n==2){
document.getElementById("container").style.backgroundImage="url(09fs/images/bg/2.jpg)";
}else if (n==3){
document.getElementById("container").style.backgroundImage="url(09fs/images/bg/3.jpg)";
}else if (n==4){
document.getElementById("container").style.backgroundImage="url(09fs/images/bg/4.jpg)";
}