function changbackground(){
	var img_bg=[];img_bg.push('/product/img/img_b1/r10138.jpg');	var length=img_bg.length;
	if(length>0){
		var randomInt=Math.floor(Math.random()*length);
		if(randomInt>(length-1)){
			randomInt=length-1;
		}
		var img_url="url("+img_bg[randomInt]+")";
		jQuery("body").css("background-image",img_url); 
		jQuery("body").css("background-repeat","repeat"); 
	}

}

changbackground();