CODEWITHSUNDEEP
javascriptxmlhttprequestsetintervalinfinite-loop
honey92
honey92

Reputation: 43

How can I keep looping over a JavaScript function with XMLHttpRequest in it, only after i get a response from that request

My requirement is to loop over(keep reinvoking) the request after i get the response from my existing xhr request. I am currently setting a timeout for 2 seconds.But I am still not sure if this works. I don't want a strict timeout as the request may take a while sometimes which is okay(as it has a db call). So any suggestions out there how i can call the function again after i get a response? 

   var request = (window.XMLHttpRequest) ? new XMLHttpRequest() : (window.ActiveXObject ? new window.ActiveXObject("Microsoft.XMLHTTP") : false);

   function htmlGen (log){
        var data_count = someNumber;
        var url = someURL;
        request.open("GET", url, true);
        request.timeout = 2000;
        request.onreadystatechange = updatePage; //some function to update my page
        request.send(null);
    }        
    function timerCntrl(command,log) {
        if (command == "start") {
            document.getElementById("start").disabled = true;
            document.getElementById("stop").disabled = false;
            timer = setInterval(function() { htmlGen(log);}, 2000);
        }else{
            document.getElementById("watchStart").disabled = false;
            document.getElementById("watchStop").disabled = true;
            clearTimeout(timer);
        }
    }

Thanks in advance :)

Upvotes: 2

Views: 78

Answers (1)

D. Pardal
D. Pardal

Reputation: 6597

This code should work. It makes a request and then waits for its response. As soon as the response arrives, it makes another request and then waits for its response... And so on...

var request = (window.XMLHttpRequest) ? new XMLHttpRequest() : (window.ActiveXObject ? new window.ActiveXObject("Microsoft.XMLHTTP") : false);
var url;
function updatePage();

async function startRequests() {
    while(true) {
        request.open("GET", url, false);
        request.onreadystatechange = updatePage; //some function to update my page
        request.send(null);
    }
}

Note that for some reason these don't get logged on the console (witch funny enough made me have to deal with a "Too Many Requests" error in SO). Also, this is really not a good thing. This is more like a DDoS than an actual HTTP request. Be careful using this.

Upvotes: 3

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