Execute a XQuery script sent by the client.
If the expected return value is a single XML document or element, it can be serialized in HTML or XHTML. If the return value is a sequence of items, items can be wrapped in elements describing their type (see format below).
mime-type: text/xml or text/html
When using format=items, the returned items are wrapped as follows:
<items> <item type="integer">12345</item> <item>some text</item> <item type="node()"><a><empty/>text</a></item> </items>
Note that if several element nodes are returned and format is not items , the result is not a well-formed document.