//Precarga imágenes
var imagen = new Array(); 
var nombre = new Array("images/B_ens_01.gif","images/B_per_01.gif","images/B_sit_01.gif","images/B_test_01.gif","images/B_home.gif","images/B_cont.gif","images/bot_eg.gif","images/B_testN_01.gif"); 
var imagen_a=new Array(); 
var nombre_a = new Array("images/B_ens_02.gif","images/B_per_02.gif","images/B_sit_02.gif","images/B_test_02.gif","images/B_home2.gif","images/B_cont2.gif","images/bot_er.gif","images/B_testN_02.gif"); 


for(i in nombre){ 
imagen[i] = new Image(); 
imagen[i].src = nombre[i]; 
}
for(i in nombre_a){ 
imagen_a[i] = new Image(); 
imagen_a[i].src = nombre_a[i]; 
}