Try with below code:
Jquery code
<script type="text/javascript">
jQuery(function() {
var date = new Date();
var currentMonth = date.getMonth();
var currentDate = date.getDate();
var currentYear = date.getFullYear();
$('#calendar123').datepicker({
minDate: new Date(currentYear, currentMonth-3, currentDate),
maxDate: new Date(currentYear, currentMonth+3, currentDate)
});
});
</script>
HTML code
<div style="font-weight: bold;">Disable Future Dates</div>
<div id="calendar123"></div>