Under Welfare and Institutions Code section 603.5, subdivision (a), jurisdiction is determined at the time the initial petition is filed in juvenile court. A petition was filed in juvenile court alleging violations of Vehicle Code sections 12500, subdivision (a), a misdemeanor, and 22350, an infraction. Following a contested jurisdictional hearing, the juvenile court dismissed the section 12500, subdivision (a) charge for insufficient evidence and found the section 22350 offense true. The court denied the minor’s motion to dismiss for lack of jurisdiction and placed the minor on court probation with conditions. Affirmed. Welfare and Institutions Code section 603.5 provides that in the county adopting the provisions of the section, “jurisdiction over the case of a minor alleged to have committed only a violation of the Vehicle Code classified as an infraction or a violation of a local ordinance involving the driving, parking, or operation of a motor vehicle, is with the superior court, . . . .” The statute does not address whether a case involving an infraction and a misdemeanor should be retained in juvenile court if the misdemeanor is dismissed. The minor did not show that some legislative purpose underlying the ambiguous statute would have been served by first requiring the juvenile court to dismiss the action and then requiring the prosecution to bring a new action on the infraction alone in the superior court in this situation. Construing section 603.5 to refer to the initial pleading in juvenile court is consistent with historical practice in the criminal and civil contexts, and with current practice in the appellate context. Once a court acquires jurisdiction, it retains it until the matter is disposed of. Jurisdiction does not depend on the outcome of the case. Here, the initial filing of the petition charging minor with a misdemeanor provided the juvenile court with jurisdiction and the fact that the misdemeanor was subsequently dismissed did not strip the court of its jurisdiction.