ZigWidgetClass adds a free text field to each widget control form on your widget admin page. The field is labelled ‘CSS Class’.
Enter a class name in the box and it will be added to the classes that WordPress applies to that widget instance. If you want to add two or more classes to a particular widget instance, simply separate them with a space.
You can deactivate and reactivate the plugin without losing your classes, and it is compatible with the Widget Logic plugin. It is also compatible with the Widget Context plugin, and has now been adapted to work with the WP Page Widgets plugin.
Read some great reviews on wordpress.org!
ZigWidgetClass has also been graced with a lovely review on this page: The Top *Non-Obvious* WordPress Plugins That’ll Make You a Better Blogger. Thanks to Brian Jackson for this:
“ZigWidgetClass. Another great little free plugin by zigpress.com. This plugin allows me to easily add custom CSS classes to my widgets. What do I use this for? I use it to deploy media queries so that I can hide certain widgets based on their resolution size. For example, on my site I have an optin box in my sidebar and my footer. On a mobile device there is no reason for it to show twice, so I add my class which pulls my media query and hide one of them.”