How to break out of AJAX polling done using setTimeout

I want to implement AJAX polling mentioned in this answer. Now I want to break out of polling when server return particular data value. How to do that?

Try something like this (where you change the condition to set continuePolling false to whatever you need):

(function poll() {
var continuePolling = true;
    setTimeout(function() {
        $.ajax({
            url: "/server/api/function",
            type: "GET",
            success: function(data) {
                console.log("polling");
                if (data.length == 0)
                {
                    continuePolling = false;
                }
            },
            dataType: "json",
            complete: function() { if (continuePolling) { poll(); }),
            timeout: 2000
        })
    }, 5000);
})();