(PHP 8)
DOMChildNode::before — Adds nodes before the node
Adds the passed nodes before the node.
nodesNodes to be added before the node. Strings are automatically converted to text nodes.
没有返回值。
DOM_HIERARCHY_REQUEST_ERR
Raised if the parent is of a type that does not allow children of the
type of one of the passed nodes, or if the node to
put in is one of this node's ancestors or this node itself.
DOM_WRONG_DOCUMENT_ERR
Raised if one of the passed nodes was created from a different
document than the one that created this node.