d3.namespace()

d3.namespace(name)

Qualifies the specified name, which may or may not have a namespace prefix. If the name contains a colon (:), the substring before the colon is interpreted as the namespace prefix, which must be registered in d3.namespaces. Returns an object space and local attributes describing the full namespace URL and the local name. For example:

d3.namespace("svg:text"); // {space: "http://www.w3.org/2000/svg", local: "text"}

If the name does not contain a colon, this function merely returns the input name.