Include the script

<script src="https://just-an-email.com/secure-line/script.js" type="text/javascript"></script>

Initialise

<script>
    // Storing the unique session id in the URL
    if (!location.hash) {
        location.hash = SecureLine.newGuid();
    }

    var uniqueId = location.hash;

    var onLineSecured = function (initiator) {
        // Secure line established, send any secure message using
        // SecureLine.send("[Event Name]", "[Optional data]")
        // [initiator === true] for first client
    };

    var onMessageReceived = function (event, data) {
        // Callback when a message is received
    };

    SecureLine.init(uniqueId, onMessageReceived, onLineSecured);
<script>

Notice this page already added a hash in the URL and ready to establish a secure connection. Open this page to another tab or device and check the console for an example.