<script type="text/javascript" charset="utf-8">
$(document).ready(function(){
 $('.chosen-select').chosen({
         no_results_text: "Oops, nothing found!"
    });
$('#search1').on('change', function (){
$('#search2').html("<option value=''>Select</option>");// add this on each call then add the options when data receives from the request
    $.getJSON('select.php', {id: $(this).val()}, function(data){
        var options = '';
        for (var x = 0; x < data.length; x++) {
            options += '<option value="' + data[x]['id'] + '">' + data[x]['Date'] + '</option>';
        }
        $('#search2').html(options);
        //$('.chosen-select').chosen();
    });
});
});
</script>

<select  id="search2" name="search" type="text" data-placeholder="Choose an Option..."     style="width:370px;" class="chosen-select" onChange="drawChart(this.value);">
<option value=""></option>
</select>