How do i prevent my browser from lagging out when some jerk floods a chat?

there is a chat with a "spam" channel and i use the spam channel to advertise my forum, but there is some jerk usually posting thousands of lines of text and i get lagged out. and of course the admins dont care, which does not surprise me cause they dont care about the communities well being. what if i have multiple opera browser windoes open? if one window lags, will the rest of the windows be unaffected?