function insertbanner(board) {
	var banners = new Array();
	
	switch(board) {
	case 'th':
		banners.push('th1.jpg');
		banners.push('th2.gif');
		break;
	case 'at':
		banners.push('at1.jpg');
		banners.push('at2.png');
		banners.push('at3.gif');
		break;
	case 'eientei':
		banners.push('eientei1.jpg');
		banners.push('eientei2.gif');
		banners.push('eientei3.png');
		banners.push('eientei4.png');
		banners.push('eientei5.gif');
		banners.push('eientei6.png');
		break;
	case 'forest':
		banners.push('forest1.jpg');
		banners.push('forest2.gif');
		banners.push('forest3.png');
		break;
	case 'gensokyo':
		banners.push('gensokyo1.gif');
		banners.push('gensokyo2.png');
		banners.push('gensokyo3.gif');		
		break;
	case 'i':
		banners.push('i1.gif');
		break;
	case 'border':
		banners.push('border1.jpg');
		banners.push('border2.gif');
		banners.push('border3.gif');
		banners.push('border4.png');
		break;
	case 'shrine':
		banners.push('shrine1.jpg');
		banners.push('shrine2.gif');
		banners.push('shrine3.gif');
		break;
	case 'sdm':
		banners.push('sdm1.jpg');
		banners.push('sdm2.gif');
		banners.push('sdm3.png');
		break;
	case 'youkai':
		banners.push('youkai1.jpg');
		banners.push('youkai2.gif');
		banners.push('youkai3.png');
		banners.push('youkai4.gif');
		banners.push('youkai5.gif');
		break;
	case 'underground':
		banners.push('underground1.jpg');
		banners.push('underground2.gif');
		banners.push('underground3.gif');
		break;
	case 'others':
		banners.push('others1.jpg');
		banners.push('others2.gif');
		break;
	case 'blue':
		banners.push('blue.jpg');
		break;
	default:
	  	//banners is empty 
	}
	
	img_str = '<img src="' + ku_boardspath
	if (banners.length == 0) {
		img_str += '/logo.gif'
	} else {
		var now = new Date();
		var sec = now.getSeconds();
		var banner = banners[sec % banners.length];
		img_str += '/' + board + '/banner/' + banner
	}
	img_str += '" alt="Logo" /><br />'

	document.write(img_str);
}