Designed my Pop Up. Decided to use the "Javascript

Designed my Pop Up. Decided to use the "Javascript to resize" option. When I load the page the Pop Up is very small and not at all how it was designed.
If I refresh the screen, like magic the Pop Up appears 'as designed'.

Can somebody have a look at http://www.molyvos.eu/test/ and tell me what is going on?

I have tried Firefox, Chrome and IE10, they all do the same thing.