Plugin: multiple-category-selection-widget (Used by 7 domains)

Turn your WordPress post categories into a search powerhouse! This plugin gives you a set of dropdown menus based on parent categories and their sub-categories. Users select one sub-category per parent, and the plugin filters posts matching the selected combination.

Available as:

• Gutenberg Block — “Multi-Category Filter” in the block inserter (new in v4)
• Classic Widget — “Multi-Category Selection” in Appearance > Widgets
• Shortcode — [mcsw] on any page or post

Features:

• AND / OR category filtering — find posts matching ALL or ANY selected categories
• AJAX chained drilldown — selecting a parent dynamically loads its children
• Pretty permalink URLs (/categories/3,5/search_type/and/order/title/)
• Ordering by title or default
• Configurable blank search behavior
• Exclude specific categories
• Lightweight — no jQuery, no external dependencies
• Pagination support
• Display form above results on category pages (optional)

Sample use case:

Real estate — set up parent categories like “Bedrooms”, “Bathrooms”, “Price Range” with sub-categories beneath them. Users filter listings by selecting from each dropdown.

Upgrading from v3.x:

• PHP sessions have been removed entirely — the URL now carries all state, which means better compatibility with caching plugins, load balancers, and modern hosting
• jQuery has been replaced with vanilla JavaScript
• CSS classes have changed from wpmcsw/wpmm to BEM-style mcsw-* classes — update any custom CSS
• The old select-chain.js in the plugin root has been replaced by js/select-chain.js