jQuery UI MultiDatesPicker demo
Pre-selected dates example
HTML
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.min.js"></script>
<script src="https://cdn.rawgit.com/dubrox/Multiple-Dates-Picker-for-jQuery-UI/master/jquery-ui.multidatespicker.js"></script>
<link rel="stylesheet" href="https://code.jquery.com/ui/1.12.1/themes/pepper-grinder/jquery-ui.css">
<link rel="stylesheet" href="https://cdn.rawgit.com/dubrox/Multiple-Dates-Picker-for-jQuery-UI/master/jquery-ui.multidatespicker.css">
<div id="myCalendar"></div>
JavaScript
var date = new Date();
$('#myCalendar').multiDatesPicker({
// preselect the 14th and 19th of the current month
addDates: ['5/2/2018','5/15/2018','5/27/2018','6/30/2018']
});