bannerFile = new Array(
	"a.jpg", "b.jpg",
	"c.jpg", "d.jpg"
) ;

document.write( "<a href=\"http://www.chuable.net/\"><img src=\"http://www.chuable.net/ss2/img/banner_high_" + bannerFile[ Math.floor( Math.random() * 4 ) ] + "\" width=\"120\" height=\"600\" border=\"0\" alt=\"好きになったら告白しよう　Sugar＋Spice2\"></a>" ) ;