function randomImg() {

	var myImages = new Array();
        
	myImages[1] = "../sistema/imagens/banner01.jpg";
	myImages[2] = "../sistema/imagens/banner02.jpg";
	myImages[3] = "../sistema/imagens/banner03.jpg";
	myImages[4] = "../sistema/imagens/banner04.jpg";
	
	var rnd = Math.floor(Math.random() * myImages.length);
	if(rnd == 0){
	rnd = 1;
	}

        if(rnd == 1){
	document.write('<style></style>');
	}
	
	document.write('<style>#banner_interna{background:url('+myImages[rnd]+') no-repeat;}</style>');
	
	}