How i can control my web site ?

[C# Programming]

Hi.

In my web site have forum.
Users can insert anything texts.I want enabled inserting just english chars and numbers, and disabled all other characters!

For example , in this forum any peoples writing native ********(like arabian, parsian ,...) and how can disable it.

Thanks. http://www.barakasoft.com/script/Forums/Images/smiley_doh.gifWe are haven't bug,just temporarily undecided problems.