[Rithlilky]

The following list is taken from "Ta'leemul Haq":

Things Not Allowed During The Khutbah

- Talking.
- Offering Sunnah and Nafl Salah.
- Eating.
- Drinking.
- To reply to any talk.
- Reciting the Qur'an etc.

All those things which disturb the Khutbah become Makruh from the minute the Imam prepares to deliver the Khutbah. The following is taken from "Bahishti Zewar (Heavenly Ornaments)":

Injuctions for Juma Sermon

1 -- It is highly execrable to offer any prayer or talk when Khutba is being delivered. But offering postponed prayer is allowed and essential.
2-- When the Khutba has begun it is essential for all present to listen it whether they are sitting near the Imam or at some distance. It his highly execrable to do anything which obstructs the hearing of Khutba. To eat, drink, talk, walk, greet, respond to greeting, to recite any prayer or to explain any religious problem during Khutba are all prohibited. It is, however, permissible for the deliverer of the Khutba to explain some religious problem during the Khutba.
3-- If the Khutba begins while one is offering Sunna or Nafl prayer, then the Sunna should be completed and the Nafl should be concluded after two Raka'ats only.
4-- It is highly execrable for the Imam or the followers to pray with raised hands during the sitting of the Imam between the two Khutbas but praying within oneself is permissible provided no words are spoken neither loudly nor in a low voice. To recite items of farewell or seperation in the Khutba of the last Friday of Ramadan is not reported from the Holy Prophet or his Companions.
5-- It is permissible to read the Khutba from a book.
6-- It is permissible for the listeners to recite Darood Sharif within themselves on hearing the holy names of the Prophet occurring in the Khutba. The following is an excerpt from a book with the name of "Sunnats":

Sunnahs of Jumu'ah (Friday)

S.8 One should listen attentively to the Khutbah even if one does not understand. One should not speak or even warn another to keep quiet while the Khutbah is in progress.

S.9 When Nabi's name is mentioned in the Khutbah, it is ja'iz (permissible) to recite Durud in the heart only (without the movement of the lips or tounge).

S.10 Between the two Khutbahs one can make Du'a. It is permissible to make Du'a without raising the hands or moving the lips (i.e. Du'a should be made in the heart only without the movement of the lips or the tounge).