Every parent is deemed to have an obligation to financially support their child, even after divorce - you can divorce a spouse, but you can't divorce a child. Just like with alimony, the amount awarded can increase or decrease depending on "changing circumstances" by an ex-spouse filing a motion with the court for a hearing to determine this, or by scheduled adjustment. New Jersey courts balance the parents' income and assets against the child's needs.
What is the relation between child support and alimony?
In calculating child support, the court first deducts alimony payments from the paying spouse's income and attributes that money as additional income to the spouse receiving it. Also, the paying spouse gets a tax deduction for his/her alimony payments, while the receiving spouse has to report child support as income on their taxes.