Platform and version requirements: JS (1.1)

@DeprecatedSinceKotlin("1.4") fun Element.addClass(
    vararg cssClasses: String
): Boolean

Deprecated: This API is moved to another package, use 'kotlinx.dom.addClass' instead.

Adds CSS class to element. Has no effect if all specified classes are already in class attribute of the element

Return true if at least one class has been added