function changeBG(id){
if(id == 1){
document['body'].style.backgroundImage = "url(backgrounds/bg01.jpg)";
}
else if(id == 2){
document['body'].style.backgroundImage = "url(backgrounds/bg02.jpg)";
}
else if (id == 3){
document['body'].style.backgroundImage = "url(backgrounds/bg03.jpg)";
}
else if (id == 4){
document['body'].style.backgroundImage = "url(backgrounds/bg04.jpg)";
}
else if (id == 5){
document['body'].style.backgroundImage = "url(backgrounds/bg05.jpg)";
}
else if (id == 6){
document['body'].style.backgroundImage = "url(backgrounds/bg06.jpg)";
}
else if (id == 7){
document['body'].style.backgroundImage = "url(backgrounds/bg07.jpg)";
}
else if (id == 8){
document['body'].style.backgroundImage = "url(backgrounds/bg08.jpg)";
}
else if (id == 9){
document['body'].style.backgroundImage = "url(backgrounds/bg09.jpg)";
}
else if (id == 10){
document['body'].style.backgroundImage = "url(backgrounds/bg10.jpg)";
}
else if (id == 11){
document['body'].style.backgroundImage = "url(backgrounds/bg11.jpg)";
}
else if (id == 12){
document['body'].style.backgroundImage = "url(backgrounds/bg12.jpg)";
}
else{
document['body'].style.backgroundImage = "url(backgrounds/bg11.jpg)";
}
}