img = new Array();
img[0] = "image/main_img01.jpg";
img[1] = "image/main_img02.jpg";
img[2] = "image/main_img03.jpg";
img[3] = "image/main_img04.jpg";
img[4] = "image/main_img05.jpg";



function setImg(){
	amount = img.length;
	No = Math.floor(Math.random()*amount);
	document.write("<img src='" + img[No] + "' border='0' width='998' height='469'> ");
}