Selectator is a jQuery-based replacement for select boxes. It supports searching, and affects the original select box directly, which is used as the data container. You can see a demo here.

<link rel="stylesheet" href="fm.selectator.jquery.css"/>
<script src="jquery-1.11.0.min.js"></script>
<script src="fm.selectator.jquery.js"></script>

$('#selectBox').selectator();

If you don't wan't to meddle with scripting, there is an alternative to activate replacement, by using inline markup.

<select multiple class="selectator" data-selectator-keep-open="true">

$('#selectBox').selectator({
    prefix: 'selectator_',             // CSS class prefix
    height: 'auto',                    // auto or element
    useDimmer: false,                  // dims the screen when option list is visible
    useSearch: true,                   // if false, the search boxes are removed and 
                                       //   `showAllOptionsOnFocus` is forced to true
    keepOpen: false,                   // if true, then the dropdown will not close when 
                                       //   selecting options, but stay open until losing focus
    showAllOptionsOnFocus: false,      // shows all options if input box is empty
    selectFirstOptionOnSearch: true,   // selects the topmost option on every search
    searchCallback: function(value){}, // Callback function when enter is pressed and 
                                       //   no option is active in multi select box
    labels: {
        search: 'Search...'            // Placeholder text in search box in single select box
    }
});

By using data-left, data-right and data-subtitle attributes you can extend the information shown in the options. These can be styled through css, and are named prefix_title, prefix_left, prefix_right and prefix_subtitle. The data in the attributes is pure html, so you can even put images here. The class attributes from the original option and optgroup elements are also added to the genererated elements

<select id="selectBox">
    <!-- Normal option tag -->
    <option value="1">This is the title</option>
    <!-- Extended option tag -->
    <option value="2" data-left="This is the left section" data-right="This is the right section" data-subtitle="This is the section under the title">This is the title</option>
</select>

It will be displayed something like this this:

Here is a list of all the css classes

• dimmer
• element: containing the single|multiple class and the options-visible|options-hidden class
  • textlength
  • chosen_items
    • chosen_item
      • chosen_item_left
      • chosen_item_right
      • chosen_item_title
      • chosen_item_subtitle
      • chosen_item_remove
    • chosen_item...
  • input
  • options
    • group_header
    • group
      • option: containing the active class
        • option_left
        • option_right
        • option_title
        • option_subtitle
      • option...
    • option: containing the active class
      • option_left
      • option_right
      • option_title
      • option_subtitle
    • option...

$('#selectBox').selectator('refresh');

or

$('#selectBox').selectator('destroy');

• IE 8+
• Chrome 2+
• Firefox 3.5+
• Safari 4+
• Opera 11+

Selectator supports language by setting labels through the plugin options.

The MIT License (MIT)

Copyright (c) 2013 Faroe Media

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.