function random()
{
	var a = new Array("system/image/001.JPG","system/image/002.JPG","system/image/003.JPG","system/image/004.JPG","system/image/005.JPG","system/image/006.JPG","system/image/012.JPG","system/image/013.JPG");
	var b = a.length;
	var c = Math.floor(b*Math.random());
	document.getElementById("maindisplay").src = a[c];
}