# JavaScript API
## XPathHelper: (xh)
```{eval-rst}
.. js:autoclass:: XPathHelper
  :members:
```
## Filter: (filter)
### ValidExpressionFilter
```{eval-rst}
.. js:autoclass:: ValidExpressionFilter
  :members:
```
### EmptyFilter
```{eval-rst}
.. js:autoclass:: EmptyFilter
  :members:
```