// https://stackoverflow.com/questions/43274559/how-do-i-restrict-past-dates-in-html5-input-type-date
// You can try this
 var maxDate = year + '-' + month + '-' + day;
    alert(maxDate);
    $('#txtDate').attr('min', maxDate);
$(function(){
    var dtToday = new Date();
    
    var month = dtToday.getMonth() + 1;
    var day = dtToday.getDate();
    var year = dtToday.getFullYear();
    if(month < 10)
        month = '0' + month.toString();
    if(day < 10)
        day = '0' + day.toString();
    
    var maxDate = year + '-' + month + '-' + day;

    // or instead:
    // var maxDate = dtToday.toISOString().substr(0, 10);

    alert(maxDate);
    $('#txtDate').attr('min', maxDate);
});


//
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="date" id="txtDate" />