I came across sites that pose a challenge to someone with little knowledge on the religion. Just as an example; to quote: number of times Jerusalem is mentioned in the Qur'an. Bear in mind that these are Jews and/or Christians that are defaming my religion.

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

It is the great favor of Allah that He has provided human beings with the means that benefit them in both their religion and their world. They may use them for enlightenment and to acquire the knowledge of Shari'a. However, Internet is technology that can be used for good or evil. You may find on Internet many Islamic sites that contain the Qur'anic, Hadith and Fiqh (jurisprudence) encyclopedias; browsing them and having access to them is very easy.
On the other hand, Muslim youth should avoid visiting those sites that are against Islam and distort the image of Muslims and their history. So, whoever cannot protect himself from the doubts nor refute them should avoid their writings and published material.
Also one must avoid visiting pornographic sites that spread evils and dissoluteness. Their aim is to destroy Muslim communities, especially Muslim youth and to uncover Muslim women. One of their intellectuals said: 'A drinking glass and a beautiful woman affect Muslim youth much more that artillery can do' .
Adhering to the religion and good conduct are the main protectors of Muslim communities because they combat dissolution, give strength to resist evil and prevent imitating non-Muslims. A poet said: 'Nations survive as long as they keep good morals and when they lack high moral standards they will be destroyed' .
In fact, enemies of Islam are at war with Islam in different fields, using various means especially, in faith, ideas, history and noble characteristics.
Therefore, Muslim youth should be aware of their poison and try their best to refute them and to uncover their schemes.
Allah knows best.