add attribute in select option
<select id="select">
<option value="1" data-foo="dogs">this</option>
<option value="2" data-foo="cats">that</option>
<option value="3" data-foo="gerbils">other</option>
</select>
// JavaScript using jQuery
$(function(){
$('select').change(function(){
var selected = $(this).find('option:selected');
var extra = selected.data('foo');
...
});
});
// Plain old JavaScript
var sel = document.getElementById('select');
var selected = sel.options[sel.selectedIndex];
var extra = selected.getAttribute('data-foo');