function changeSearch(buscador) {
     if (buscador == 'google'){
     	document.getElementById ("ultimasform").style.display = "none";
     	document.getElementById ("impresaform").style.display = "block";
        document.getElementById ("srchimpresab").checked = true;
     }else{
     	document.getElementById ("ultimasform").style.display = "block";
     	document.getElementById ("impresaform").style.display = "none";
        document.getElementById ("srchultimasb").checked = true;
     }
}