+++ /dev/null
----
-title: onLoading
-name: options-onloading
----
-
-The onLoading parameter is called when the tree data is loading. This gives us the opportunity to display a loading signal.
-
-Callback looks like this:
-
-```js
-function (is_loading, node, $el)
-```
-
-* **is_loading**: boolean
- * true: data is loading
- * false: data is loaded
-* **node**:
- * Node: if a node is loading
- * null: if the tree is loading
-* **$el**:
- * if a node is loading this is the `li` element
- * if the tree is loading is the `ul` element of the whole tree