var no=Math.round(Math.random()*99)+1;
if (no<=20){
document.write("<a href='http://union.dangdang.com/transfer/transfer.aspx?from=P-102383&backurl=http://book.dangdang.com'><img src=/book/img/book1.gif border=0 width=468 height=60></a>");
}else if (no<=40){
document.write("<a href='http://union.dangdang.com/transfer/transfer.aspx?from=P-102383&backurl=http://book.dangdang.com'><img src=/book/img/book2.gif border=0 width=468 height=60></a>");
}else if (no<=60){
document.write("<a href='http://union.dangdang.com/transfer/transfer.aspx?from=P-102383&backurl=http://book.dangdang.com'><img src=/book/img/book3.gif border=0 width=468 height=60></a>");
}else if (no<=80){
document.write("<a href='http://union.dangdang.com/transfer/transfer.aspx?from=P-102383&backurl=http://book.dangdang.com'><img src=/book/img/book4.gif border=0 width=468 height=60></a>");
}else{
document.write("<a href='http://union.dangdang.com/transfer/transfer.aspx?from=P-102383&backurl=http://book.dangdang.com'><img src=/book/img/bangj1.gif border=0 width=468 height=60></a>");
}