// no direct access
defined( '_JEXEC' ) or die( 'Restricted access' );

// Import library dependencies
jimport('joomla.plugin.plugin');

class plgContentEya extends JPlugin
{

function plgContentEngageya( &$subject, $config )
{
parent::__construct( $subject, $config );

}
/**
* Plugin method with the same name as the event will be called automatically.
*/
function onAfterDisplayContent( &$article, &$params, $limitstart)
{//Echo script there
echo "script works";
// Plugin code goes here.
// You can access parameters via $this->params.
return "<script src='http://widget.eya.com/sprk.1.0.2.js' type='text/javascript'></script>";
}
}




http://docs.joomla.org/Plugin/Events/Content