Remain focus and prevent character input except tab key

Is there anyway that i can remain focused on the input element after selecting a date in jQuery datepicker? Also is there anyway that i can prevent user from typing anything but enabling the tab key? I'm currently using prevent default method but i only need to enable the tab key. Thank you. Here is my current method.

$('body').on('focus',".dateSem",function() {
    $(this)
      .datepicker({
        changeMonth: true,
        changeYear: true,
        changeDay: true,
        showButtonPanel: true,
        dateFormat: 'yy/MM/dd',
        showMonthAfterYear: true,
        monthNames: ["01", "02", "03", "04",
          "05", "06", "07", "08", "09", "10",
          "11", "12"
        ],
        monthNamesShort: ["1", "2", "3", "4",
          "5", "6", "7", "8", "9", "10",
          "11", "12"
        ],
        dayNamesMin: ["日", "月", "火", "水", "木",
          "金", "土"
        ],
        minDate: new Date,
        currentText: '今日を選択',
        closeText: '確定',
        onClose: function(dateText, inst) {
          $(this).datepicker(
            'setDate',
            new Date(inst.selectedYear,
              inst.selectedMonth,
              inst.selectedDay));
        }
      });
    $(this).keydown(function(e) {
      e.preventDefault();
    });

  });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

I have made a simple implementation with the following html (please do not forget to include jquery and jqueryui)

<label>Date pick 1</label>
<input type="text" class="mydatepicker" />
<br />
<label>Test focus</label>
<input type="text" /><br />
<label>Date pick 2</label>
<input type="text" class="mydatepicker" />
<br />
<label>Simple text to check tab focus</label>
<input type="text" />

And the javascript code

$('.mydatepicker')
 .keydown(function(e){
  if(e.keyCode==9){
     return true;
  }
  return false;
})
.datepicker({
  onSelect:function(date){
   $(this).focus();
  }
});

And the explanation

You select all input fields with class .mydatepicker and assign an onkeydown event where you disable all key input except if the the keycode is equal to 9 (which mean equal to tab)

Then you transform them also datepickers and inside the onSelect function (which runs after the user picks a date) and you call $(this).focus() where this is the current input element