function bgStyle(){
	var wall = new Array();
	wall[0] = "/img_top/back01.jpg";
	wall[1] = "/img_top/back02.jpg";
	wall[2] = "/img_top/back03.jpg";
	wall[3] = "/img_top/back04.jpg";
	wall[4] = "/img_top/back05.jpg";
	wall[5] = "/img_top/back06.jpg";
	wall[6] = "/img_top/back07.jpg";
	var rnd = Math.floor((Math.random() * 100)) % wall.length;
	document.write('<style type="text/css">#back { background-image:url(' , wall[rnd] , '); }</style>');
}

var xiti = 0, yiti = 0;
function bgGo(){
	if(!document.getElementById) return;
	var bcgr = document.getElementById("back"); 
	bcgr.style.backgroundPosition = xiti + "px " + yiti + "px";
	xiti += 0; if(xiti > 720) xiti = 0;
	yiti -= 1; if(yiti < -323) yiti = -323;
	setTimeout("bgGo();", 50);	
}