Chosen (SO 28974740)

HTML

<link REL="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/chosen/1.1.0/chosen.css"/>
<div id="myPage">
    
</div>
<div id="myPage2"></div>
<script type="text/template" id="mySelectTemplate">
    <select class="mySelect">
        <option value=''></option>
        <option value="1">One</option>
        <option value="2">Two</option>
        <option value="3">Three</option>
        <option value="4">Four</option>
        <option value="5">Five</option>
        <option value="6">Six</option>
        <option value="7">Seven</option>
    </select>
</script>

<script src="//cdnjs.cloudflare.com/ajax/libs/chosen/1.1.0/chosen.jquery.min.js"></script>

JavaScript

$(function(){
    //get the template (select)
    var template = $('#mySelectTemplate').html();
    
    //add to the page (mocking a dynamic element)
    $('#myPage').append(template);
    
    //init the chosen plugin
    $('#myPage .mySelect').chosen();
    
    //listen for change event
    $('#myPage .mySelect').chosen().change(function(e){
        //when 'one' is selected, add another chosen. 
        console.log(this.value);
        if ($(this).val() == 1) {
            $('#myPage2').append(template);
            $('#myPage2 .mySelect').chosen();
            
            //The listener for the new select has to be attached after the select is created
            //listen for change on second chosen
            $('#myPage2 .mySelect').chosen().change(function(e){
                console.log('change');
            });
        }
    });
    
});