var max      = 10;
  var nrImages = 4;
  function makeImages() {
        this[0]     = "/images/banner_mini_vitrine.png";
		this[1]     = "/images/banner_mini_muitoporpouco.gif";
		this[2]     = "/images/banner_mini_advogata.gif";
		this[3]     = "/images/banner_mini_pret.gif";

    this.length = nrImages;
  }
  function makeLinks() {
   	    this[0]     = "http://vitrinevirtual08.blogspot.com";
		this[1]     = "http://www.muitoporpouco.com.br";
		this[2]     = "http://advogatabrecho.blogspot.com";
		this[3]     = "http://pretaporterbrecho.blogspot.com";
    this.length = nrImages;

  }
  var vetImages = new makeImages();
  var vetLinks  = new makeLinks();
  var x = Math.round(Math.random()*max);
  var y    = max / nrImages;
  for(var cont = 1;cont*y <= max;cont++) {
    if (x <= (cont*y)) {
      document.write("<a href="+vetLinks[cont-1]+" target=blank><img  src="+vetImages[cont-1]+" border=0></a>");
      break;
    }
  }