Specify the amount that's preselected.
Query string example: ?amount=20
Default: nothing
Note, doesn't really do any validation right now. So negative values "work" and nonsense strings "work".
Specify the amount in the four donation amount buttons.
Query string example: ?presets=1, 2, 3, 4
Default: 20, 10, 5, 3
Note, must be four options. It reverts to the defaults if it has more or less than 4 options.
Specify the currency.
Query string example: ?currency=usd
Default: usd
Available options: mxn, nok, aud, brl, cad, chf, czk, dkk, eur-de, eur-fr, gbp, hkd
Note, only works with lowercase values.
Specify the donation frequency.
Query string example: ?frequency=monthly
Default: single
Available options: single, monthly