on firefox? how?
Answers:
firefox by itself does not give any option for blocking sites,but there are some addons/plugins (like procon) u can use for parental control[make sure ur version number is same as what the plugin is written for]
for details check this page
http://forums.mozillazine.org/viewtopic.php?t=338572
blocking sites?
This article contents is create by this website user, FireFoxAnswer.com doesn't promise its accuracy.