I say, and with God's success: Wudu (ablution) is not invalidated by laughter at all, but it has specific conditions, which are: 1. The one praying must be of age; even if a child laughs, his wudu is not invalidated because it is not a transgression against him. 2. The one praying must be awake; even if he falls asleep in prayer in any position, laughter does not invalidate his wudu. 3. The one praying must be either in a state of tayammum (dry ablution) or wudu; even if he laughs during a prayer that requires ghusl (full ablution), it invalidates the prayer, not the ghusl. 4. The laughter must occur in a prayer that includes bowing and prostration; this is to exclude the funeral prayer and the prostration of recitation, as laughter does not constitute an event in them, but it invalidates the prayer in which the laughter occurred. Likewise, outside of prayer, it is even more so; because when the text is contrary to analogy, it is limited to its specific case, and its case is the absolute prayer, so it is limited to it, and it does not constitute an event in other cases. Refer to: Sharh al-Wiqayah 2: 33-34, Tabyeen al-Haqaiq 1: 11, Fath Bab al-Inayah 1: 68, al-Ikhtiyar 1: 16-17, and Mukhtalif al-Riwayah p. 344-345, and God knows best.