Check Internet Connectivity – Javascript


In this article, we are going to show you how you can show a toast/alert message to the user if their internet gets disconnected.

Video Tutorial:

First, you need to download a library called Toastify. You can download it from GitHub.

After that, you need to include it in your project like this:

<link rel="stylesheet" type="text/css" href="js/toastify.css" />
<script src="js/toastify.js"></script>

Then you need to download another library called Checknet. You can also download it from GitHub too.

You need to include that library as well:

<script src="js/checknet.min.js"></script>

After that, the following code will show a toast message when the internet is down. And it will keep displaying until the network is restored or the toast is manually closed:


    // create global toastify instance
    var toastify = null;

    // check when the internet is disconnected
    Checknet.addEventListener('dropped', function() {

        // show a toast message
        toastify = Toastify({
            text: "Internet connection lost.",
            duration: -1,
            newWindow: false,
            close: true,
            gravity: "bottom", // `top` or `bottom`
            position: "center", // `left`, `center` or `right`
            stopOnFocus: true, // Prevents dismissing of toast on hover
            style: {
                background: "red",
            onClick: function() {} // Callback after click

    // callback when the connection is restored
    Checknet.addEventListener('restored', function() {

        // hide the toast if it is being displayed
        if (toastify != null) {

    // start listening for network connectivity


Refresh the page now and try to disconnect your laptop from the internet. You will immediately see a toast message saying that the internet connection is lost.

Then re-connect the internet, the toast message will be removed automatically. You do not have to refresh the page.

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