There are 4 Farz in Wudhu

The wudhu is incomplete if a FARDH is omitted.

What WUDHU considers to be fardh items:

1. Cleaning the "face" from one ear lobe to the other and from the "forehead" to the bottom part of the chin.
2. Cleaning both arms, encompassing the "elbows."
3. Mashing up one-quarter of the "head."
4. Cleaning both feet, being sure to get the "ankles" clean.

The following eight things shatter the wudhu:

They are referred to as wudu nawagis or breakers:
(1) leaking pee or feces, or emerging from any of the aforementioned areas.
(2) Gases are released.
(3) the exudation of pus or blood from any bodily part.
(4) gagging with a mouthful.
(5) to lay the head or lie down to sleep
(6) To pass out from a disease or for any other reason.
(7) turning insane or insane.
(8) Laughing during the namaz also separates the wudu chin and the earlobes.