DOMNode->insertBefore() Adds a new child before a reference node &reftitle.description; DOMNode DOMNodeinsertBefore DOMNodenewnode DOMNoderefnode This function inserts a new node right before the reference node. If you plan to do further modifications on the appended child you must use the returned node. &reftitle.parameters; newnode The new node. refnode The reference node. If not supplied, newnode is appended to the children. &reftitle.returnvalues; The inserted node. &reftitle.errors; DOM_NO_MODIFICATION_ALLOWED_ERR Raised if this node is readonly or if the previous parent of the node being inserted is readonly. DOM_HIERARCHY_REQUEST_ERR Raised if this node is of a type that does not allow children of the type of the newnode node, or if the node to append is one of this node's ancestors or this node itself. DOM_WRONG_DOCUMENT_ERR Raised if newnode was created from a different document than the one that created this node. DOM_NOT_FOUND Raised if refnode is not a child of this node.