JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://ajax.microsoft.com/ajax/jquery.validate/1.7/jquery.validate.js"></script>
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.2/themes/ui-lightness/jquery-ui.css">
<select name="choices">
    <option>Method1</option>
    <option>Method2</option>
</select>

<select multiple="multiple" name="sub">
</select>

JavaScript

options = [
    ['1A','1B','1C'],
    ['2A','2B','2C']
];

$('select[name=choices]').change(function() {
    var idx = $(this).children(':selected').index();
    var set = '';
    for(var i = 0, len = options[idx].length; i < len; i++) {
        set += '<option>' + options[idx][i] + '</option>';
    }
    $('select[name=sub]').html(set);
}).change();