# knowledge:categoryList

A loop on a subset of the category hierarchy. The total number of categories displayed in a page can't exceed 500.

You must have access to the category you set as `rootCategory` to get a list of any categories. To list categories available to a user, see the [Knowledge Support REST APIs.](https://developer.salesforce.com/docs/atlas.en-us.api_rest.meta/api_rest/resources_knowledge_support.htm)

## Example

List descendents of the 'phone' category. 'phone' is in the 'product' category group.

```visualforce
<select name="category">
    <knowledge:categoryList categoryVar="category" categoryGroup="product" rootCategory="phone" level="-1">
        <option value="{!category.name}">{!category.label}</option>
    </knowledge:categoryList>
</select>

```

## Attributes

| Attribute Name  | Attribute Type | Description                                                                                                                                                        | Required? | API Version | Access |
| --------------- | -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------ | --------- | ----------- | ------ |
| `ancestorsOf`   | String         | If specified, the component will enumerate the category hierarchy up to the root (top-level) category. rootCategory can be used to specify the top-level category. |           | 43.0        |        |
| `categoryGroup` | String         | The category group to which the individual categories belong.                                                                                                      | Yes       | 43.0        |        |
| `categoryVar`   | String         | The name of the variable that can be used to represent the article type object in the body of the categoryList component.                                          | Yes       | 43.0        |        |
| `id`            | String         | An identifier that allows the component to be referenced by other components in the page.                                                                          |           | 14.0        | global |
| `level`         | Integer        | If specified with rootCategory, the component will stop at this specified depth in the category hierarchy. -1 means unlimited.                                     |           | 43.0        |        |
| `rendered`      | Boolean        | A Boolean value that specifies whether the component is rendered on the page. If not specified, this value defaults to true.                                       |           | 14.0        | global |
| `rootCategory`  | String         | If specified without ancestorsOf, the component will loop on the descendents of this category.                                                                     |           | 43.0        |        |