hi :) I would like to call / trigger a function when the cart loads but.. don't know how to do that. ;) The function is part of the 3rd party extension mod (AwoCoupon Customer Balance mod) and it's located in www/components/com_awocoupon/controller.php - function apply_voucher_balance(). When the function gets called the apply button gets clicked. By default you must click it manually but I would like to automate that process. I need the simplest solution - it just needs to work. :) Can it be done by copy and paste?
Greets!
my Jommla: 2.5.28
my Virtuemart: 2.6.22
			
			
			
				Create a Joomla system plugin. Check in onAfterDispatch function. Refer - https://docs.joomla.org/Plugin/Events Then use a if clause to check if it is the cart page. 
Example plugin:
<?php
defined('_JEXEC') or die;
class PlgSystemCustom extends JPlugin
{
	public function onAfterDispatch()
	{
		$app = JFactory::getApplication();
		
		if($app->isAdmin())
		{
			return false;
		}
		
		if(JRequest::getCmd('option') == 'com_virtuemart' && JRequest::getCmd('view') == 'cart' && JFactory::getDocument()->getType() == 'html')
		{
			// It is cart page after load
			// Your codes goes here
		}
	}
}
			
			
			
				Thanks! I will try that :)
			
			
			
				So according to your instructions I've created the plugin but I'cant get this work.  :-\
In the .xml file I have:
<?xml version="1.0" encoding="utf-8"?>
<extension version="2.5" type="plugin" group="system">
        <name>awo-auto-apply-balance-on-cart</name>
        <files>
                <filename plugin="awo-auto-apply-balance-on-cart">awo-auto-apply-balance-on-cart.php</filename>
                <filename>index.html</filename>
        </files>
</extension>
and the .php contains:
<?php
defined('_JEXEC') or die;
class PlgSystemCustom extends JPlugin
{
	public function onAfterDispatch()
	{
		$app = JFactory::getApplication();
		
		if($app->isAdmin())
		{
			return false;
		}
		
		if(JRequest::getCmd('option') == 'com_virtuemart' && JRequest::getCmd('view') == 'cart' && JFactory::getDocument()->getType() == 'html')
		{
		
		function apply_voucher_balance() {
		//JRequest::checkToken() or jexit( 'Invalid Token' );
		
		$handlerclass = 'AwoCoupon'.AWOCOUPON_ESTORE.'CouponHandler';
		if (!class_exists( $handlerclass )) require JPATH_ADMINISTRATOR.'/components/com_awocoupon/helpers/estore/'.AWOCOUPON_ESTORE.'/couponhandler.php';
		call_user_func(array($handlerclass,'process_customer_balance'));
		
		if ($return = JRequest::getVar('return', '', 'BASE64')) {
			$return = base64_decode($return);
			if (!JUri::isInternal($return)) $data['return'] = '';
		}
		if (empty($return)) $return = 'index.php?';
		JFactory::getApplication()->redirect(JRoute::_($return));
	}
	
		}
	}
}
			
			
			
				It seems you do not have knowledge of PHP coding or on Joomla plugin development. You have an invalid PHP codes and also a invalid Joomla plugin xml with respect to the plugin class. 
Please need first correct your PHP codes and call function correctly. Then you need create a correct manifest file for the plugin. Now install it and enable it from Joomla plugin manager. Read this carefully if you want learn more - https://docs.joomla.org/J3.x:Creating_a_Plugin_for_Joomla
I would suggest you better take help from some PHP programmer. 
			
			
			
				You are right I'm not a programmer :) but I thought that, with the help of more experienced users, I could try to handle it by myself. :) Thanks for your help.
			
			
			
				That being said :) since you're a programmer and we have already got so far maybe you could give me a few additional tips? For instance could you tell me what's wrong with my .xml code? - I don't have any errors on install. Also can I use your code (without additional motifications) or it's just an example? And finally what command shoud I use to call my function? Should it be $dispatcher = JDispatcher::getInstance();?
Regards
			
			
			
				ok, my mistake :D "the plugin class" silly error :D thanks!
			
			
			
				One more thing - how to change this plugin to call function not 'when in the cart' but 'when adding to the cart' (or when total in the cart is > 0). ?
Regards