setInterval not on hikashop_checkout_page

-- url of the page with the problem -- : scale-fpv.de/index.php/produkte/warenkorb
-- HikaShop version -- : Essential: 2.4.0
-- Joomla version -- : 3.4.1
-- Browser(s) name and version -- : Mozilla

Hello everyone,

I have wrote an small JavaScript function, to set the height of two DIVs dynamic, so that they looks like the same.

The Function work on every side of the page, but not in the hikashop_checkout_page.

the DIV was set is #content2_mdl_end see the code below.

var conToHeight = setInterval(function () {
	            var con2height = $('#content2').height() - 8;
	            $('#content2_mdl_end').height(con2height);
	        }, 500);

Hi,

about the link,
the link: http://scale-fpv.de/index.php/produkte/warenkorb
work if I klick in, but you see the problem only if you have something in your cart. So include something e.g. from http://scale-fpv.de/index.php/produkte/schrauben

TypeError: el is null	
	checked = el.checked,

function displayRegistration(el)
{
	var value = el.value,
[b]286	checked = el.checked,[/b]
	name = document.getElementById("hikashop_registration_name_line"),
	username = document.getElementById("hikashop_registration_username_line"),
	pwd = document.getElementById("hikashop_registration_password_line"),
	pwd2 = document.getElementById("hikashop_registration_password2_line"),
	registration_div = document.getElementById("hikashop_checkout_registration"),
	login_div = document.getElementById("hikashop_checkout_login_form");

if someone is logged in, the script is running, as well on the cart.

"components/com_hikashop/views/order/view.html.php" I coud not find the code in this file but in this one:
"components/com_hikashop/views/checkout/view.html.php"
and I changed it and it works very well, thank you very much.