Does not pass weight or environment from Javascript Buttons

[JakePT]

When used with the PayPal Javascript buttons (https://github.com/paypal/JavaScriptButtons) the cart does not pass on the data-weight and data-host attributes. You can see this by looking at the hidden inputs in the cart popup. Price, shipping, weight units, merchant, and number all go through, but weight and host (eg. Sandbox) do not.

Other attributes may not work, but these are the ones that I've found.

[fabriziotappero]

Here is an implementation of PayPal Minicart were shipping costs are based on item weight. Shipping calculation happens instantly and is shown as an item in the main Cart.

Any feedback is welcome.

http://fabriziotappero.github.io/minicart-plus/index.html