Question

I have this code in a html file that checks for connectivity, but the problem here is that it takes about 10 seconds to throw the alert message box to indicate the connection is lost. I want to know if there’s a much faster way to inform the user that the connection is lost without having to wait.
Strictly JS thanks…

JS code:

<script language="JavaScript">
function SubmitButton()
{
    if(navigator.onLine)
    {
            document.getElementById('SubmitBtn').style.visibility='visible';
    }
    else
    {
        document.getElementById('SubmitBtn').style.visibility='hidden';
    }
}
function Online() 
{ 
    var status=false;
    status= navigator.onLine;
    if(status!= true)
    {
        alert('Network connectivity is lost, please try again later');
    }
}
</script>

Calling it in html file here:

<INPUT name="ccMCA1input" type="checkbox" onclick="ccMCA1.ccEvaluate(),Online()" value=False>

Answer 1

navigator.onLine is the only built-in property which can be checked (and not reliable btw).
You could create a XHR request to a reliable server, and check whether any response is being received.