Hi nauna,
To disable the weekends in jQuery UI Datepicker you need to set the beforeShowDay property value to $.datepicker.noWeekends.
Then all the Weekends will be disabled in the date picker control.
Check this example. Now please take its reference and correct your code.
HTML
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>jQuery UI Datepicker Disable Weekend</title>
<link rel="stylesheet" href="https://code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css" />
<script type="text/javascript" src="https://code.jquery.com/jquery-1.12.4.js"></script>
<script type="text/javascript" src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<script type="text/javascript">
$(function () {
$("#txtDate").datepicker({
defaultDate: "+1w",
changeMonth: true,
numberOfMonths: 1,
beforeShowDay: $.datepicker.noWeekends
});
});
</script>
</head>
<body>
<input type="text" id="txtDate" />
</body>
</html>
Demo
