use WWW::Mechanize::Firefox;
my $mech = WWW::Mechanize::Firefox->new(autoclose => 0);
$mech -> get("your own url");
my $count = 0;
my $retries = 100;
while ($retries-- and ! $mech->is_visible( xpath => '//*[@value="your own content"]' )) {
	$count++;
	print "count: $count\n";
	sleep 1;
	#Do your login stuff here.
	if ($mech -> success()) {
		#Do stuff only once the login step succeeds.
	}
}
die "Timeout" unless $retries;