[jQuery] How to trigger jQuery action from a php else branch?

[Magnificent]

I have a login system that has a slideup/slidedown show/hide function
for a forgot password link.  It is hidden by default and it's
triggered with toggle().  Works just fine.  I have php validation on
that forgot password text field so if someone tries to submit with
that field empty they get an error message telling them to enter their
email address so we can send them a new password.

The issue I'm having is when that error message is triggered, the
forgot password text field is hidden, where I want to have it shown as
it's a bit jarring to have it suddenly go away and they have to click
the trigger to show it again.

Anyone have any ideas how I can do this?

//FORGOT PASSWORD
if (isset($_POST['forgot_password'])) {
     logic here to send user a new password
} else {
     TRIGGER JQUERY HERE SO FORGOT PASSWORD IS SHOWN

     //report the errors
     echo '<div id="errors"><span>The following error(s) occurred:</
span>';

     echo '<ul>';
     foreach($errors as $error) {
          echo "<li>$error</li>";
     }
     echo '</ul></div>';
}