is_plugin_active ( $plugin )
- (string) plugin Path to the plugin file relative to the plugins directory.
- (bool) True, if in the active plugins list. False, not in the list.
- Introduced in WordPress: 2.5.0
- Deprecated in WordPress: —
Determines whether a plugin is active.Only plugins installed in the plugins/ folder can be active.
Plugins in the mu-plugins/ folder can't be "activated," so this function will
return false for those plugins.
For more information on this and similar theme functions, check out
the [Conditional Tags](https://developer.wordpress.org/themes/basics/conditional-tags/) article in the Theme Developer Handbook.