1. add-class
| Chapter 3. Commands which are specific to w2x |

## 1. add-class

    add-class(class, before-class?, element?)

Add CSS class `class` to the list of “interned” CSS classes of element `element`. Does nothing at all if element `element` already has this CSS class.

For this command to work, command `parse-styles` must have been invoked in order to “intern” the CSS classes found in all the elements of the document being edited.

`class`

  The CSS class name to be added.

`before-class`

  Specifies before which class in the list of interned CSS classes of element `element`, `class` should be inserted. Defaults to "", which means: at the end of the list.

  - `before-class` may be the empty string "", which means add `class` at the end of the list.

  - `before-class` may be a class name. CSS class `class` is inserted in the list before class name `before-class` if found, at the end of the list otherwise.

  - `before-class` may be a class pattern. CSS class `class` is inserted in the list before the first class name matching pattern `before-class` if found, at the end of the list otherwise.

    A class pattern has the following syntax: `/`pattern`/` or `^`pattern`$` (which is equivalent to `/^`pattern`$/`), where `pattern` is a regular expression pattern.

`element`

  The element to which `class` should be added. Defaults to the context node, if the context node is an element.

Examples:

    (: Append "role-xref" to the list of classes of context element. :)
    add-class("role-xref");

    (: Insert "role-xref" before "c-Hyperlink"
       in the list of classes of context element. :)
    add-class("role-xref", "c-Hyperlink");

    (: Insert "role-xref" before first class matching "^c-.+$"
       in the list of classes of context element. :)
    add-class("role-xref", "^c-.+$");

    (: Append "role-figcaption" to the list of classes of $captionPara. :)
    add-class("role-figcaption", "", $captionPara);

See also `remove-class`.

Related XPath extension functions: `get-class`.

Chapter 3. Commands which are specific to w2x |  | 2. add-rule