undef $/; # to absorb the whole file in a single read.
open FILE, $filename;
$all = <FILE>;

$all =~ s/\.html/\.asp/g; # this will substitue the .html to .asp globally

# this takes the part in between the body tags...

$all =~ s{^.*?\<body.*?\>(.*)\</body.*?\>.*?$}
	 {$1}isx;

print OUTFILE $all;

close FILE;