The page I am generating will list all my servers in a table and there is a column called Ping with a button to trigger it. The column’s ID is generated based on the server’s hostname. For example:

  Ping!

Once the button in the td is clicked, the button will be replaced with the ping time in millisecond and automatically updated every 2 seconds.

When I was writing the function runForever I encountered a jQuery problem. In the selector, I am unable to select the id, e.g. $("#ping_server1.example.com"), and I figured that out it was a escaping problem. In the console provided by the browser’s web tool, I am able to modify the ID manually but not by js script.

// host is passed down in runForever
$("#ping_" + host.replace(/\./g, "\\\\.")).text(String(delta) + "ms");

The concatenation does not work, but manual type without concatenation does work! I have to use the oldschool way, see my final code:

$(document.getElementById('ping_' + host)).text(String(delta) + "ms");

The entire runForever function is:

function runForever(host)
{
    ping("http://" + host).then(function(delta) {
        $(document.getElementById('ping_' + host)).text(String(delta) + "ms");
    }).catch(function(err) {
        $(document.getElementById('ping_' + host)).text(err);
    });
    setTimeout(function() {runForever(host);}, 2000);
};