gistfile1.js

function add_new_option() {
		$('#calendarbyuser').select2('container').select2('close');
		// add random value
		var today = new Date();
		var new_option_val = today.getTime();
		var new_option_name = prompt("Please enter your option","New Option "+today.getSeconds());
		if(new_option_name != null)
		{
		  $('#calendarbyuser').append('<option value='+new_option_val+'>'+new_option_name+'</option>');
		  $('#calendarbyuser').select2('val', new_option_val);
		}
	}