How to show modal popup window on login in joomla

Wanted to show an article in a modal popup window to the user when log-in to the site first time & the article is updated as well. So that created a system plugin & triggered the onAfterRender event. Checked the userlastvisitdate. If its 0000-00-00 00:00:00 excuted a javascript code which shows popup modal to the logged in user. Its easy to write what i did but very diffcult at the time of coding. code is as follows

function onAfterRender()

{

$user = &JFactory::getUser();

$js = '';

$plugin = JPluginHelper::getPlugin( 'system', 'popupmodal' );

$plugin_params = new JParameter( $plugin->params );

$first_article = $plugin_params->get('firstlogin_article');

if($user->lastvisitDate == "0000-00-00 00:00:00")

{

$js = <<<EOT

<script>

var dummylink = new Element('a', {

href: "index.php?option=com_content&view=article&id=<?php echo $first_article; ?>&tmpl=component" ,

rel: "{handler: 'iframe', size: {x: 350, y: 350}}"

});

SqueezeBox.fromElement(dummylink);

</script>

EOT;

}

$user =''; // i stuck at this line cause when user logged in still i was getting lastvisitdate 0.

$body = JResponse::getBody();

$body = str_replace('</body>', $js.'</body>', $body);

JResponse::setBody($body);

}

Half work was done here. Now needed to show this popup modal to all the user of site when they log-in when article which showing in popup modal updated. It was tricky first we need to check whether that article has been updated. To check that we triggered onAfterRoute & execute the follwing code which checks article id & whether the task is save if it is then update lastvisitDate for all user so that our above condition satisfied & every user can see popup modal on log-in.

function onAfterRoute()

{

$id = JRequest::getVar('id');

$task = JRequest::getVar('task');

$plugin = JPluginHelper::getPlugin( 'system', 'popupmodal' );

$plugin_params = new JParameter( $plugin->params );

$frst_art = $plugin_params->get('firstlogin_article');

if($id == $first_article && $task == "save")

{

$db = JFactory :: getDBO();

$query = 'UPDATE #__users SET lastvisitDate = "0000-00-00 00:00:00"';

$db->setQuery($query);

$db->query();

}

}

I'll save your work you can download the plugin here