The judge of the juvenile court shall control all proceedings during the hearings with a view to the expeditious and effective ascertainment of the jurisdictional facts and the ascertainment of all information relative to the present condition and future welfare of the person upon whose behalf the petition is brought. Except where there is a contested issue of fact or law, the proceedings shall be conducted in an informal nonadversary atmosphere with a view to obtaining the maximum co-operation of the minor upon whose behalf the petition is brought and all persons interested in his welfare with such provisions as the court may make for the disposition and care of such

minor.