if(document.images){
	//4_0
	var sn_4_1_over=new Image(); sn_4_1_over.src="../img/sn_4_1_over.gif";
	var sn_4_1_off=new Image(); sn_4_1_off.src="../img/sn_4_1_off.gif";
	var sn_4_2_over=new Image(); sn_4_2_over.src="../img/sn_4_2_over.gif";
	var sn_4_2_off=new Image(); sn_4_2_off.src="../img/sn_4_2_off.gif";
	var sn_4_3_over=new Image(); sn_4_3_over.src="../img/sn_4_3_over.gif";
	var sn_4_3_off=new Image(); sn_4_3_off.src="../img/sn_4_3_off.gif";
	var sn_4_4_over=new Image(); sn_4_4_over.src="../img/sn_4_4_over.gif";
	var sn_4_4_off=new Image(); sn_4_4_off.src="../img/sn_4_4_off.gif";
	var sn_4_5_over=new Image(); sn_4_5_over.src="../img/sn_4_5_over.gif";
	var sn_4_5_off=new Image(); sn_4_5_off.src="../img/sn_4_5_off.gif";	
}