javascript – How to free resources gathered by XMLHttpRequest?

I made a fairly simple web application that uses XMLHttpRequest to periodically request (every 2 seconds) new information from an HTTP server and animate objects on the screen accordingly.

Apparently, each time a new request is made, the application gathers a little more customer memory. After leaving it running for one or two weeks, the page was blocked with the following error in the registry:

Error loading resource: net :: ERR_INSUFFICIENT_RESOURCES

I can see the memory allocated to the process using Chrome's developer tools. Just keep increasing slowly (field "resources", highlighted in the image):

Chrome network analysis

I used the basic code for XMLHttpRequest and placed it in a setInterval (function, 2000).

Basic XMLHttpRequest function:

var url = "http://" + io.server + "/get/vars/snapshot?name=testVar";

var request = new XMLHttpRequest();

request.open("GET", url);
request.onload = function () {
    if (request.status == 200) {
        console.log(request.responseText);
    }   
}
request.send(null);

Does anyone know what this "resources" information Chrome shows in developer tools -> Network?