Use unique scope identifiers for items 

Scope identifiers, or sids, uniquely identify each item within the XFDL code. Each item on a page should have a different sid to differentiate it from other items on that page. You may use the following characters: a-z, A-Z, 0-9, dollar sign ($), and underscore (_). Spaces are not permitted.

Each item should have a unique sid to so that the Viewer and Designer can tell them apart. Older versions of the Viewer allow forms to contain duplicate sids, but treat them unpredictably. For example, computes involving two items that share the same sid, called duplicate sids, may behave incorrectly, or may not function at all. As a result, when hand-coding forms you should create unique sids for each item on every page. It is good practice to choose sids that describe the purpose of the item, such as "Print_Button".

If you create your forms using the Designer , it automatically creates unique sids by numbering each item as it is created. For example, LABEL1, LABEL2, and so on.

Note: If you open a hand-coded form in Designer 2.0 or later or Viewer 4.5 or later, duplicate sids are automatically flagged as errors and you will not be able to complete the form.

Example

You must establish sids in the first line of an item's code, as shown in the following example:



However, items on separate pages may have duplicate sids. For example, if you had a print button on multiple pages, each button's sid could be "Print_Button", as shown below:



Duplicate sids on separate pages are permitted because each item’s reference includes the sid of its page. Therefore, if a compute involved the first button in the code above, the full reference would be:

PAGE1.Print_Button

This allows the Viewer to differentiate between buttons with the same name on different pages.

Exceptions to this practice

There are no exceptions to this practice.

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