function imgpreload(){
	files = new Array(
	"http://www.joshi-chat.com/img_parts/perf_menu_entrance_over.gif",
	"http://www.joshi-chat.com/img_parts/perf_menu_preference_over.gif",
	"http://www.joshi-chat.com/img_parts/perf_menu_mailbox_over.gif",
	"http://www.joshi-chat.com/img_parts/perf_menu_points_over.gif",
	"http://www.joshi-chat.com/img_parts/perf_menu_time_over.gif",
	"http://www.joshi-chat.com/img_parts/perf_menu_result_over.gif",
	"http://www.joshi-chat.com/img_parts/perf_menu_pay_over.gif",
	"http://www.joshi-chat.com/img_parts/perf_menu_manual_over.gif");
	preimgs = new Array();
	for(i=0;i<files.length;i++){
		preimgs[i] = new Image();
		preimgs[i].src = files[i];
	}
}

function chgbtn(btnname,btnno,btntype){
	document.images[btnname].src='http://www.joshi-chat.com/img_parts/'+btnname+btnno+'.'+btntype;	
}