Period pass dropdown displays in Chrome, but not Safari?

Hi there,

Could you please explain to me why, when using the 'period pass' (£9.99 for a days access in my case), why does Chrome display a dropdown when clicking the 'period pass' button on the front end, yet Safari goes straight to the PayPal checkout page?

Also - how exactly does that dropdown work (the one with Twitter, Facebook and WP register)? For example, when I click the WP register button it takes me to the WP Admin page and not a register page? This would imply that it's actually asking you to login not register? It won't let you skip this step and just pay either (like Safari does).

Could you please explain this further. Thanks.