11.9.8 Serialization as application/x-www-form-urlencoded

This format represents an extension of the [XHTML 1.0] form content type application/x-www-form-urlencoded with specific rules for encoding non-ASCII and reserved characters.

This format is not suitable for the persistence of binary content. Therefore, it is recommended that forms capable of containing binary content use another serialization method.

The steps for serialization are as follows:

1. Each element node is visited in document order. Each relevant element that has no child element nodes (i.e., each leaf element node) is selected for inclusion, including those that have no value (no text node). Note that attribute information is not preserved.

2. Element nodes selected for inclusion are encoded as EltName=value, where = is a literal character, EltName represents the element local name, and value represents the contents of the text node. If the element does not have a text node (it has no value), an empty string is used. The separator character {sep} from the separator attribute on submission is used between pairs of encoded name/value pairs, e.g. EltName1=value1{sep}EltName2=value2{sep}EltName3=value3. Note that contextual path information is not preserved, nor are namespaces or namespace prefixes. As a result, different elements might serialize to the same name.