TinyNav.js is a tiny jQuery plugin (362 bytes minified and gzipped) that converts <ul> and <ol> navigations to a select boxes for small screen. It also automatically selects the current page and adds selected="selected" for that item.
This isn't the first plugin to do this and it doesn't provides a lot of options, but it might be the smallest (file size).
For instructions and demo go to http://tinynav.viljamis.com
Licensed under the MIT license.
Copyright (c) 2011-2012 Viljami Salminen, http://viljamis.com/
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
v1.03 (2012-03-15) - Adds new option called "header", thanks to @jorde
v1.02 (2012-03-07) - Some performance improvements and a bug fix
v1.01 (2012-01-04) - Code Refactoring
v1.00 (2011-12-31) - Release