Canadian/US Address Data Capture

When I fill out an interactive form that prompts for an address that could be Canadian or US; I am constantly disappointed with the data capture experience. Usually the form uses a single field to capture both state and province: State/Province:________ with a drop down that lists all states and provinces. And then a single field to capture both zip code and postal code: Zip/postal Code:__________ . Or worse, the captions on the field are biased toward a US address, but allow you to enter values for a Canadian address. I.e. you get prompted for a zip code, but it allows you to type in a postal code.

The exercise for this blog entry is to come up with a data entry experience that is tailored according to country. The samples build on the work from the previous blog entry that dealt with validating a Canadian postal code.

Single Schema

The premise of the exercise is that you want to have only one place in your data where you store an address – whether Canadian or US. The samples are based on generating this XML data:


Validate a zip code

To be fair, I thought I should try to offer advanced validation for Zip codes.  After all, I did a whole blog entry on Canadian postal codes.  No offence to my American friends, but zip codes are not nearly as interesting as postal codes. When I poked around to see if I could do more advanced validation beyond the standard Zip or Zip+4, I was pretty disappointed. The only thing I found was that there is a correlation between the first digit and the state. For example, for zip codes starting with a “1”, the state must be one of: Delaware, New York or Pennsylvania. Better than nothing. The sample forms have a utility function to validate a zip code:

* validateZipCode() – validate whether a field holds a valid zip code
* @param vZip — the zip code field. If the validation fails, this field
* will be modified with an updated validation message
* @param vState (optional)– a corresponding field value holding the
* state abbreviation.  This method will make sure the first digit of
* the zip code is valid for this state.
* @return boolean — true if valid, false if not.

Keystroke validation

For the Canadian postal code validation, I introduced a change event that forced the entry to upper case. This time around, I have extended that concept to disallow keystrokes that would cause an invalid zip or postal code. A few words of explanation about some of the xfa.event properties that were used:

  • xfa.event.change – represents the delta between the previous change and the current one. Usually this is the content of a single keystroke. However it can also contain the contents of the clipboard from a paste operation. This property can be updated in the change event script to modify the user’s input. It can be set to an empty string to swallow/disallow user input.
  • xfa.event.newText – represents what the field contents will look like after the changes have been applied. Modifying this property has no effect.
  • xfa.event.selEnd – The end position of the changed text. Usually when the user is typing, we are positioned at the end of string, but the user could be inserting characters at any position.

Here is the change event script for the zip code:

Address.Address.USAddress.Zip::change – (JavaScript, client)
// restrict entry to digits and a dash
if (xfa.event.change.match(/[0-9\-]/) == null)
    xfa.event.change = "";

// Allow the hyphen at the 6th character only
if (xfa.event.change == "-" && xfa.event.selEnd != 5)
    xfa.event.change = "";

// If the 6th character is a digit, and they’re typing at the end, insert the hyphen
if (xfa.event.change.match(/[0-9]/) != null &&
    xfa.event.newText.length == 6 &&
    xfa.event.selEnd == 5) 

    xfa.event.change = "-" + xfa.event.change;

var vMax = 9;
if (xfa.event.newText.indexOf("-") != -1)
    vMax = 10;

// don’t allow any characters past 9 (10 with a hyphen)
if (xfa.event.newText.length > vMax)
    xfa.event.change = "";

In hindsight, I could have done a better job with this script.  It is still possible to enter invalid data.  e.g. after adding the hyphen at the 6th character, the user could cursor back and insert digits, forcing the hyphen beyond the 6th character.  A better approach might be to modify the validateZipCode() method so that it will validate partial zip codes.  Then block any user input that doesn’t result in a correct partial zip code.

There is a similar block of logic for the postal code change event.

Customizing Data Capture

The really hard part of this data capture problem is how to tailor the input by country. I have two samples that take different approaches.

Sample 1: Different subforms for each country

In this sample, the strategy is to use two subforms for data capture. One subform that has a province and postal code field for Canadian addresses. One that is tailored for capturing a US address.

To make this design work, we create two subforms (CanadianAddress and USAddress), set the binding of each subform to “none”. Then bind the individual fields to the address data. The reason for this approach is that we want both subforms to populate the same data. Multiple fields are allowed to bind to the same XML data element, but you cannot bind multiple subforms to the same XML data.

Show/hide logic. It is not enough to simply set the presence of the subforms to visible/invisible. A hidden field will still run its validation script. We want to make the subforms optional and add/remove them as appropriate. To make this exercise a little more interesting, I assumed that we were not in a flowed layout. Now the problem is that unless you’re in a flowed context, Designer does not allow you to make the subform optional (under the binding tab). However, the XFA runtime does not have this restriction. There are two workarounds: 1) Modify the source in the XML view 2) fix it in script. I chose the latter approach. Subform occurrences are managed by the <occur> element. By default, the address subforms will be defined as:

<occur initial="1" m
ax="1" min="1"/>

We can change the minimum via script in order to make them optional:

Address.Address.Country::initialize – (JavaScript, client)
USAddress.occur.min = "0";
CanadianAddress.occur.min = "0";

Once the subforms are defined, simply place them on top of each other at the same page location. When changing country from the country drop down list, the subforms will toggle on/off accordingly:

Address.Address.Country::validate – (JavaScript, client)
// Choose which subform address block to use depending on the country
_USAddress.setInstances(this.rawValue == "U.S." ? 1 : 0);
_CanadianAddress.setInstances(this.rawValue == "Canada" ? 1 : 0);

Sample 2: One Subform, change the field properties

In this sample, the strategy is to create one set of dual-purpose fields. One field to capture either a postal code or a zip code and one field to capture either a state or a province. When the country changes, we modify the field definitions so that they behave appropriately. The changed properties included the caption text, the picture clauses and the contents of the state/province drop down lists. The validation that happens in the change event and in the validation script needs to branch to accommodate the appropriate context.

The logic to toggle the field definitions looks like:

Address.Address.Country::validate – (JavaScript, client)
if (this.rawValue == "U.S." && 
    ZipPostal.caption.value.text.value != "Zip Code:")
    ZipPostal.caption.value.text.value = "Zip Code:";
    ZipPostal.ui.picture.value = "";
    ZipPostal.format.picture.value = "";

    StateProv.caption.value.text.value = "State:";

    StateProv.addItem("Alabama", "AL");
    StateProv.addItem("Alaska", "AK");
    StateProv.addItem("Arizona", "AZ");
  . . .
    StateProv.addItem("Wyoming", "WY");
} else if (this.rawValue == "Canada" &&
           ZipPostal.caption.value.text.value = "Postal Code:"
    ZipPostal.caption.value.text.value = "Postal Code:";
    ZipPostal.format.picture.value = "text{A9A 9A9}";
    ZipPostal.ui.picture.value = "text{OOO OOO}";

    StateProv.caption.value.text.value = "Province:";

    StateProv.addItem("Alberta", "AB");
    StateProv.addItem("British Columbia", "BC");
    StateProv.addItem("Manitoba", "MB");
. . .
    StateProv.addItem("Yukon", "YT");

Comparing the approaches

  • Both samples work in Reader version 7, 8 and 9
  • Sample 2 is easier to design, even though it requires more script.
  • Sample 1 is easier to extend in the event that you want your address block to handle more than just two countries.
  • Sample 1 requires dynamic forms.
  • Sample 2 could be modified to work for forms with fixed-pages. You would need to change the form design so that the caption is represented by a protected field (captions can be modified only on dynamic documents).