function cargaCombos(){
    var combo = busquedaSimpleForm.seleccion;
    combo.options.length=0;

    for(i=0; i<destinos.length;i++){
        combo.options[i] = new Option(destinos[i][1], destinos[i][0]);
    }
    var index = destinos.length;
    for(j=0; j<tipos.length;j++){
        combo.options[index] = new Option(tipos[j][1], tipos[j][0]);
        index++;
    }
 combo.options[0].selected = true;

}