function bgChange() {
	bgImg = new Array();
	bgImg[0] = "img/body_bg02.jpg";
	bgImg[1] = "img/body_bg03.jpg";
	n = Math.floor(Math.random()*bgImg.length);
	if ( n == 1 ) {
		document.getElementsByTagName("body")[0].style.backgroundImage = "url(" +bgImg[n]+ ")";
	}
}