Preselecting hidden items in the donation form
If you wish, for example, to have a Christmas campaign just be processed through a specific link and not directly show "Christmas Special" on your general form, you can make this possible through the selection of a hidden form-item.
If your FundraisingBox version includes item visibility, then you can manage the visibility of the individual items under "Settings > Donation Form > View: advanced settings > Items". An item MUST be added to the form before it can be pre-selected. The visibility check box enables you to make certain items visible or hidden. Only the visible items appear on the live donation form.
In order to pre-fill a hidden item, go to the tab "Button generator" and select the desired item. Behind the item name you can see the item ID in brackets. Click on "Generate Code" and you will receive item widgets, donations buttons and a link.
Items can be pre-selected with the parameters "fb_item_id" and "fb_item_id_fix". Note, however, that hidden items can only be selected as "fix".