What is your question? I would think it is a pretty straight forward thing. You need HTML::Parse module. Go through lwp's documentation. It is pretty solid.
#save $var->content as html file (to match with next day's file) in th
+e normal manner (not shown here)
#for the earlier saved html
# now compare $txt_on_the_page & $txt_on_the_old_page. I have put very
+ less code with very optimistic approach. But with little effort you
+will get what you need.