Input type date not showing value - html

Question

I've got a project in Symfony2 (v. 2.2.11) in which I've got a calendar (fullCalendar) and when a user clicks in a day I open a overlay with a form and my start and end date got the selected day as value (format yyyy-MM-dd). If I inspect the element there's a value with the correct date but is not showing in input box, only shows when I click a date (I'm using jquery date chooser) the value appears in the input box (the new one).
This is my FormType code for start and end date:
->add('startDate','date',array(
'label'=>'ueb_crossfit_class.form.event.labels.startDate',
'widget' => 'single_text',
'format' => "yyyy-MM-dd",
'attr' => array('class' => "input-date datepicker")
))
->add('endDate','date',array(
'required' => false,
'label'=>'ueb_crossfit_class.form.event.labels.endDate',
'widget' => 'single_text',
'format' => "yyyy-MM-dd",
'attr' => array('class' => "input-date datepicker")
))
This is the generated input (for start date):
<input id="ueb_crossfiterz_bundle_classbundle_eventtype_startDate" class="input-date datepicker hasDatepicker" type="date" value="2013-12-27" required="required" name="ueb_crossfiterz_bundle_classbundle_eventtype[startDate]">
I've already tested with Firefox and Chrome and both doesn't show the value but only Firefox show that red line in input (as appear in image).
[UPDATE]
As asked in comments here's my js code for initializing fullCalendar:
$(function () {
var date = new Date();
var d = date.getDate();
var m = date.getMonth();
var y = date.getFullYear();
$('#calendar-holder').fullCalendar({
header: {
left: 'prev, next',
center: 'title',
right: 'month,agendaWeek,agendaDay,'
},
lazyFetching:true,
selectable: true,
timeFormat: {
// for agendaWeek and agendaDay
agenda: 'HH:mm{ - HH:mm }', // 5:00 - 6:30
// for all other views
'': 'HH:mm{ - HH:mm }' // 7p
},
eventSources: [
{
url: Routing.generate('ueb_class_getEvents'),
type: 'POST',
error: function() {
//alert('There was an error while fetching Google Calendar!');
}
}
],
eventClick: function(event) {
clickEvent(event);
return false;
},
select: function(start, end, allDay){
selectEvent(start, end, allDay);
}
});
});