Select box filter is a free Chrome add-on developed by ota-meshi. It falls under the category of Browsers and the subcategory of Add-ons & Tools. This add-on allows users to filter options in select boxes by simply Ctrl+Clicking (or Command+Clicking) on the select box. Once in filter mode, an input field appears next to the select box. Users can then enter the keyword they want to filter by, and the options in the select box will be filtered accordingly.

One of the great features of Select box filter is that it only displays the filter input field for the select box that was Ctrl+Clicked (or Command+Clicked), which minimally disrupts the layout of the page. Additionally, the filtering is done using the display property, so it does not affect the functionality of pages that use the selectedIndex property in JavaScript. Furthermore, the filtering is case-insensitive and does not differentiate between uppercase and lowercase letters, hiragana and katakana, or full-width and half-width characters.

With Select box filter, users can easily filter select box options and find the desired choice quickly and efficiently.