What is the ruling on using a mobile phone in the mosque to browse the internet?

It is preferable for one who enters a mosque to enliven it with prayer, remembrance [dhikr], and supplication [du'a], as this is the purpose of mosques, just as the Prophet, peace and blessings be upon him, said: "These mosques are not fit for any of this urine or filth; rather, they are for the remembrance of Allah, the Mighty and Majestic, prayer, and the recitation of the Quran." As for browsing the internet in the mosque, it is not forbidden if the browsing is permissible. However, if the browsing is forbidden, then it is even more forbidden in the mosque, just as Ibn Taymiyyah mentioned that what is forbidden outside the mosque becomes even more forbidden inside it.