XForms, Formatting Numbers

Motivation

You want the view portion of your form to add formatting information to numbers. For example, you want your US currency to be stored in the model as 12345.6789 but the view to display at $12,345.68. Note that the dollar sign is used as a prefix, commas are added and the decimal is rounded to two digits.

Ideally, we would like to use a simple CSS function to indicate that all currency should be formatted using the standard number picture formats such as "$#,###.##".

Method

If all browsers supported the XPath 2.0 format-number() function, this would be trivial. Till then the developer will need to resort to workaround such as using JavaScript and the XML Binding language (XBL).

Sample Code

nodeset="instance('invoice')/Total" calculate="round((instance('invoice')/Tax + instance('invoice')/SubTotal) * 100) div 100"/>

References

Mozilla page on XForms custom controls

The following discussions on the XForms mailing lists might be helpful.

Dan McCreary's Post to the Mozilla XForms discussion group

John Boyer's Comments on Number Formatting in XForms

acknowledgement of the currency format needs in the 2001 working draft of XForms

Where this page came from

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