如何限制可见选择的js上的所选项目多选择下拉列表

Question

我正在使用选择的js进行多项选择。如果所选项目计数更多5我想显示前五个并添加切换选项以查看其他所选项目。请建议

output += '<select data-placeholder="" class="chosen-select" multiple style="width:100%;" name="email[]" tabindex="4">';
for (var x in email_list) {
    var emailListHidden = email_list[x]['email'];
    output += '<option selected value="' + emailListHidden + '">' + emailListHidden + '</option>';
}

for (var el in all_emails) {

    var all_emails_lists = all_emails[el][0];
    output += '<option value="' + all_emails_lists + '">' + all_emails_lists + '</option>';

}
output += '</select></div><br/>';

//hide duplicates from list
var map = {};
$('select option').each(function () {
    if (map[this.value]) {
        $(this).remove()
    }
    map[this.value] = true;
})

//multi-select input box
var config = {
    '.chosen-select': {}
}
for (var selector in config) {
    $(selector).chosen(config[selector]);
}