$(document).ready(function() {

var randomImages = ['back1','back2','back3','back4','back5','back6','back7','back8','back9',];
var rndNum = Math.floor(Math.random() * randomImages.length);

$("#conteudo").css("background-image","url(images/" + randomImages[rndNum]  + ".gif)");


var randomNumbers = ['1','2','3']
var rndNum = Math.floor(Math.random() * randomNumbers.length);
$("#conteudo a").remove();
$("#conteudo").append("<a href=\"mailto:box@box1824.com.br\" class=\"logobox"+ randomNumbers[rndNum] +"\"><img src=\"images/marca"+ randomNumbers[rndNum] +".gif\" /></a>");

});