Item positioning specifies where each item is displayed on a form. When creating signature filters, always ensure that you secure the positioning information of all of your form items. Even items that you have omitted
from your signitems
option should have a signoptions
option filter that keeps their item positions. While itemlocation
is the most obvious option that contains positioning information, there are other options that could potentially effect the location, size, or appearance of an item, such as size
, or scrollhoriz
. The Designer automatically secures these options, unless you choose otherwise.
Setting signatures to sign positioning information helps prevent someone from using unsigned items and options to obscure signed items. If items are obscured, readers could potentially misunderstand what they are signing. This may allow users to repudiate their signed forms based on an incorrect perception of what they were signing.
Consider an online insurance policy application. If a flaw in a signature filter permitted someone to obscure contract terms that are crucial to the user’s understanding, the contract could be successfully challenged.
There are two types of positioning information: absolute and relative. Absolute positioning requires that you position items using x and y coordinates in pixels. The relative positioning scheme, however, places items in relation to other items. If you use relative positioning, you must sign the anchor item
so that it cannot be moved. If someone moves an unsecured anchor item, it automatically displaces all of the items that are dependent upon it for positioning information. Regardless of the type of item positioning you use, you must secure the positioning information or a malicious user could displace form items and obscure important information.
Using this practice allows you to lock down the appearance and location of items that otherwise cannot be signed. For example, you might exclude certain compute items with an omit
filter. However, to prevent malicious modification of those items, you can specify options to secure using the keep
You should set signatures to sign all item positioning information, regardless of whether positioning is absolute or relative. However, whenever practical, you should use absolute rather than relative positioning.
The following diagrams illustrate a portion of a brokerage application form. In this form, the check boxes and fields are positioned below the anchor labels using relative positioning. These anchor labels are not secured by a signature filter. As you can see in the second diagram, LabelB and its dependent items have been moved to obscure LabelA and its dependent items.
For example, in the following code the signature filter omits LabelB but keeps its itemlocation
This signitemrefs option omits LABELB from the signature filter.
This signoptionrefs option secures LABELB's itemlocation.
If you use an omit
signature filter, you automatically secure the form's item positioning, except for those items you specifically exclude. If you do exclude some items with an omit
filter, pair it with a keep
filter to secure the item positioning information.
is not the only option that can potentially affect the location, size, or appearance of an item. If an item is omitted from the signature filter, you should consider adding all of these options to a keep filter. These options include:
Exceptions to this practice
There are no exceptions to this practice.