XPath provides a standard set of functions for string manipulation, and these are felt to be adequate for forms-based applications. This section defines string function property provided by the XForms core function library.
Function property takes a single string argument that names a feature of an XForms implementation and returns a string value describing that feature. Possible values for the argument to function property along with the defined return values are shown in Table 6.2.
We illustrate the use of function property in Figure 6.3 with a sample that displays information about the XForms client that is processing the page.
Figure 6.3 Displaying information about the XForms processor using function property .
< group xmlns ="http://www.w3.org/2002/xforms"> This XML powered web form uses XForms < output value ="property('version')"/> and conforms to < output value ="property('conformance-level')"/> </ group >
When loaded into a browser that implements all features of XForms 1.0, this might display the output shown in Figure 6.4.
Figure 6.4 Time-stamping a time card using function now .
< model id ="tc" xmlns ="http://www.w3.org/2002/xforms" xmlns:xsd ="http://www.w3.org/2001/XMLSchema"> < instance > < tc xmlns ="">...< stamp xsi:type ="xsd:date"/></ tc > </ instance > < submission id ="submit-tc"> < action > < setvalue ref ="/tc/stamp" value ="now()"/> < message >Submitted your time-card with time-stamp < output ref ="/tc/stamp"/> </ message ></ action > </ submission ></ model >
Table 6.2. Function Property ”Arguments and Return Values
This XML powered Web form uses XForms 1.0 and is being displayed by an XForms user agent that conforms to profile XForms full .