i did this
$total_size = $ENV{CONTENT_LENGTH};
my $str=qq[new Object({"state":"uploading", "size":"$total_size", "received":"0","files_done":"0"})];
open(F,">$c->{htdocs_tmp_dir}/$sid.html");
print F $str;
close F;
open(F,">$c->{htdocs_tmp_dir}/test.html");
print F $str...