var randObjects=[
	'<a href="http://www.out-standing.jp/"><img src="./img/common/banner1.jpg"></a>',
	'<img src="./img/common/banner2.jpg">',
	'<a href="http://www.fine-motorschool.co.jp/index.html"><img src="./img/common/banner3.jpg"></a>'
];
function randWrite() {
	var rr = parseInt(Math.random() * randObjects.length);
	document.write(randObjects.slice(rr,rr+1)[0]);
	randObjects.splice(rr,1);
}