(No version information available, might be only in CVS)
DomNode->previous_sibling — Returns the previous sibling of node
This function returns the previous sibling of the current node. If there is no previous sibling it returns FALSE (< 4.3) or NULL (>= 4.3). You can use this function to iterate over all children of a node as shown in the example.
See also domnode_next_sibling().