opendir(DIR, $jscriptdir) or die("Can't open $jscriptdir");
my @jsFiles = grep(/\.js$/, readdir(DIR));
closedir(DIR);
foreach my $jsFile (@jsFiles) {
    # do whatever
}

##</code><code>##

use File::Find;
use IO::File;

find(\&wanted, $jscriptdir);

sub wanted {
	if (/\.js$/) {
		my $fh = new IO::File($_) or die("Can't open $File::Find::dir/$_");
		while (<$fh>) {
			# your while here
		}
		$fh->close();
	}
}