imgdata_off = new Array("images/menu1.jpg","images/menu2.jpg","images/menu3.jpg","images/menu4.jpg");
	imgdata_on = new Array("images/menu1_on.jpg","images/menu2_on.jpg","images/menu3_on.jpg","images/menu4_on.jpg");

	preimg_off = new Array();
	preimg_on = new Array();

	for(j=0;j<imgdata_off.length;j++){
		preimg_off[j] = new Image();
		preimg_off[j].src = imgdata_off[j];
		preimg_on[j] = new Image();
		preimg_on[j].src = imgdata_on[j];
	}