First of all I am anticipating that you are using jquery date picker.
So I would recommend you to use ID for both instead of class. Still this should work out. As you are using date picker in textbox, that value can be obtained through..
$(".datepicker").datepicker(
{
onSelect: function()
{
var dateObject = $(this).datepicker('getDate');
}
});
This returns back the date selected. Please try with this if this works. Else post back your queries.
Thanks
:)