CSS :

.my-icon .date {
  background:#fff url(https://cdn1.iconfinder.com/data/icons/cc_mono_icon_set/blacks/16x16/calendar_2.png)  93% 50% no-repeat ;
 }

HTML :

<div class="my-icon" form-group style="padding-left:0px ;margin-bottom:15px;">
    <label>From: </label>
    <input type="text" name="fromdt" id="fromdt" class="form-control date" value="<?= isset($_POST['fromdt']) ? $_POST['fromdt'] : "" ?>" readonly>
    </div>

JS :

    $("#fromdt").datepicker(
        {
            dateFormat: 'yy-mm-dd',
            maxDate: '+0D',
            changeYear: true,
            changeMonth: true,
            yearRange: "-100:+0"
        }
    );