Hi,

JS Jobs can not change other component code so JS Jobs can not control login and redirect after login.

You may change the code of com_user to control redirect.
components/com_user/controller.php
method : login()
code...........
if(!JError::isError($error))
{
// Redirect if the return url is not registration or login
if ( ! $return ) {
$return = \'index.php?option=com_user\'; change this line
with
index.php?option=com_jsjobs&c=jsjobs&view=employer&layout=formjob
}

$mainframe->redirect( $return );
}
else
{
// Facilitate third party login forms
if ( ! $return ) {
$return = \'index.php?option=com_user&view=login\';
}

// Redirect to a login form
$mainframe->redirect( $return );
}

Their is an other article to redirect.
docs.joomla.org/How_do_you_redirect_user..._successful_login%3F