JSFiddle - React, Tailwind, and code Playground
by Nick Craver
HTML
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/dot-luv/jquery-ui.css">
<select multiple="multiple" size="5" id="supply_cities_select">
<option value="2">city1</option>
<option value="3">city3</option>
<option value="4">city4</option>
<option value="5">city5</option>
<option value="6">city6</option>
<option value="7">city8</option>
</select>
Current: <span></span>
JavaScript
var src;
$("#supply_cities_select").change(function() {
src = $(this).children(":selected").slice(-5).map(function(i) {
return '&c'+(i+1)+'='+this.value;
}).get().join('');
$("span").text(src);
});