var imagenes=new Array("grilleriaweb.gif", "animal-centerweb.gif", "reptiline_principal.jpg", "tecnofauna.jpg", "habistatweb.jpg", "procagesweb.jpg", "entomoneitorweb.jpg");
var enlaces=new Array("http://www.lagrilleria.com", "http://www.animal-center.es", "http://www.reptiline.com", "http://www.tecno-fauna.com/", "http://www.habistat.es", "http://www.pro-cages.com", "http://www.entomoneitor.com");
var numeros = new Array(0, 1, 2, 3, 4, 5, 6);
var cache_imagenes = new Array();
var banner1, link1;
var contador = -1, im_length;

function Cambia_Imagen()
{
	if (contador < 0)
	{
		precargarImagenes();
		contador = 0;
	}
	if (contador >= im_length)
	{
		fisherYates(numeros);
		contador = 0;
	}
	banner1.src = cache_imagenes[numeros[contador]].src;
	link1.href = '' + enlaces[numeros[contador++]];
}

function precargarImagenes()
{
	var i, j;
 	im_length = imagenes.length;

	for (i = 0, j = im_length; i < j; i++)
	{
		cache_imagenes[i] = new Image();
		cache_imagenes[i].src = '/patrocinadores/img/' + imagenes[i];
	}
	banner1 = document.getElementById('banner_1');
	link1 = document.getElementById('link_b_1');
	fisherYates(numeros);
	setInterval('Cambia_Imagen()', 4000);
}

function fisherYates ( myArray ) {
  var i = myArray.length;
  if ( i == 0 ) return false;

  while ( --i ) {
     var j = Math.floor( Math.random() * ( i + 1 ) );
     var tempi = myArray[i];
     var tempj = myArray[j];
     myArray[i] = tempj;
     myArray[j] = tempi;
   }
}