ماذا يفعل الإمام إذا انتقض وضوؤه أثناء خطبة الجمعة؟

Purity (tahara) is not a condition for the Friday sermon (khutbah). Therefore, if the preacher's ablution (wudu) is nullified during it, there is no harm in him continuing. After completing the sermon, he has the choice either to appoint someone else to lead the people in prayer or to perform ablution and then lead them himself, provided there is no long interval between the sermon and the prayer.