Ionic Digital Clock Java Script

I try to include a Digital Clock in my ionic app. I have the function digiClock.js in a separate Class.

    $(document).ready(function() {
    // Create two variable with the names of the months and days in an array
    var monthNames = ["Januar", "Februar", "März", "April", "Mai", "Juni", "Juli", "August", "September", "Oktober", "November", "Dezember"];
    var dayNames = ["Sonntag", "Montag", "Dienstag", "Mittwoch", "Donnerstag", "Freitag", "Samstag"]

    // Create a newDate() object
    var newDate = new Date();
    // Extract the current date from Date object
    newDate.setDate(newDate.getDate());
    // Output the day, date, month and year   
    $('#Date').html(dayNames[newDate.getDay()] + ", " + newDate.getDate() + ' ' + monthNames[newDate.getMonth()] + ' ' + newDate.getFullYear());

    setInterval(function() {
        // Create a newDate() object and extract the seconds of the current time on the visitor's
        var seconds = new Date().getSeconds();
        // Add a leading zero to seconds value
        $("#sec").html((seconds < 10 ? "0" : "") + seconds);
    }, 1000);

    setInterval(function() {
        // Create a newDate() object and extract the minutes of the current time on the visitor's
        var minutes = new Date().getMinutes();
        // Add a leading zero to the minutes value
        $("#min").html((minutes < 10 ? "0" : "") + minutes);
    }, 1000);

    setInterval(function() {
        // Create a newDate() object and extract the hours of the current time on the visitor's
        var hours = new Date().getHours();
        // Add a leading zero to the hours value
        $("#hours").html((hours < 10 ? "0" : "") + hours);
    }, 1000);
});

In my index.html I call digiClock.js so:

<script src="js/digiClock.js"></script>

<div>
<button class="clock" id="clockButton">
    <div id="Date"></div>
    <ul>
        <li id="hours"></li>
        <li id="point">:</li>
        <li id="min"></li>
        <!-- <li id="point">:</li> -->
        <!-- <li id="sec"></li> -->
    </ul>
</button>

But in my Digital Clock is not shown. What can be the reason? How can I call a seperate JS class in Ionic? What do I need to adjust in the class specifically for Ionic?

Thanks.