Summary:
The postfield element specifies a field name and value for transmission to an origin server during a URL request. The actual encoding of the name and value will depend on the method used to communicate with the origin server.

Attributes:

Name	Data type	Mandatory	Default	Description
id	String	X		A unique name for the tag within the deck
class	String	X		A name of a class of which the tag is a member
name	String			Specifies the variable name.
value	String			Specifies the variable value.