my @pre_events = (qw(focus));
my @post_events = (qw(blur));

$mech->field('#username', 'admin', undef, \@pre_events, \@post_events);
$mech->field('#password', '*******', undef, \@pre_events, \@post_events);
$mech->click_button(id => 'loginBtn');

##</code><code>##

$mech->eval('document.getElementById("username").focus()');
$mech->sendkey(string => 'admin');
$mech->eval('document.getElementById("password").focus()');
$mech->sendkeys(string => '*******');
$mech->click_button(id => 'loginBtn');