function drop_down() {

	if (document.forms[0].elements[0].selectedIndex == 0) {
	} else if (document.forms[0].elements[0].selectedIndex == 9) {
		link_file += "glossary.htm";
	} else if (document.forms[0].elements[0].selectedIndex == 16) {
		link_file += "i/game/index.htm";
	} else if (document.forms[0].elements[0].selectedIndex == 18) {
		link_file += "derby-stallion/bc-input.htm";
	} else {
		alert("�������ł�");
		link_file = "";
	}
	
	if (link_file != "") {
		window.location.href = link_file;
	}
	
}