| Value | Meaning |
|---|---|
| always | This element must always have an explicit closing tag (or a self-closing tag). An unclosed tag will lead to a parse error. In XML, all tags are "always". |
| implicit | Close tags are optional, but are implied when absent. As a result, these elements cannot have any content, and any close tags must be adjacent to the open tag. |
| never | This element is void and must never have a closing tag. It is always implicitly closed right after opening. A close tag is always an error. This mode can be used for strict parsing of HTML5 void elements. |
The logic for how to handle a node's closing tags.