if(document.images){
	//5_0
	var sn_5_1_over=new Image(); sn_5_1_over.src="../img/sn_5_1_over.gif";
	var sn_5_1_off=new Image(); sn_5_1_off.src="../img/sn_5_1_off.gif";
	var sn_5_2_over=new Image(); sn_5_2_over.src="../img/sn_5_2_over.gif";
	var sn_5_2_off=new Image(); sn_5_2_off.src="../img/sn_5_2_off.gif";
	var sn_5_3_over=new Image(); sn_5_3_over.src="../img/sn_5_3_over.gif";
	var sn_5_3_off=new Image(); sn_5_3_off.src="../img/sn_5_3_off.gif";
}