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Editorial Team
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Asked: 2026-05-23T12:27:55+00:00

I have this code: <script type=text/javascript> var url = http://www.xxxxx.xxx/xxxxxxxxx; var txt; var id1;

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I have this code:

<script type="text/javascript">
var url = "http://www.xxxxx.xxx/xxxxxxxxx";

var txt;
var id1;
var id2;
var imgarres = [];
var imgarr = [];
var imgels = [];

function getdata() {
    if (id1){clearTimeout(id1);}
    if (id2){clearTimeout(id2);}

    var xhr = new XMLHttpRequest();
    xhr.open('GET',url, true);
    xhr.setRequestHeader('Cache-Control', 'no-cache');
    xhr.setRequestHeader('Pragma', 'no-cache');

    xhr.onreadystatechange = function() {
        if (xhr.readyState == 4)  {
            txt = xhr.responseText;

            var r = txt.indexOf('<b class="fl_r">Online</b>');
            var el = document.createElement("div");

            el.innerHTML = txt;

            var n = imgprocess(el);     
            var nam = el.getElementsByTagName("title")[0].innerHTML;

            if (r != -1) {
                var notification = webkitNotifications.createNotification('plus.gif',  nam, 'online!!' );
                notification.show();
                var id1 = setTimeout(getdata, 60000);
            } else {
                var notification = webkitNotifications.createNotification(n,  nam, 'offline!!' );
                notification.show();
                var id2 = setTimeout(getdata, 600000);
            }
        }
    }

    xhr.send();    
}

function imgprocess(text) {
    imgels = text.getElementsByTagName("IMG");
    for (var i=0;i< imgels.length;i++) {
        if (imgels[i].src.indexOf(parse(url)) != -1) {
            imgarr = imgels[i];
        }
    }

    for (var p=0; p< imgarr.length; p++) {
        if (imgarr[p].parentNode.nodeName=="A") {
            imgarres = imgarr[p];
        }
    }

    var z = imgarres[0].src;
    return z; 
}

function init() {
    getdata();
}
</script>
</head>
<body onload="init();">

When I execute this code, error says “src cannot be read of undefined” about var z = imgarres[0].src; When I remove src from that line, extension works without errors, but
imgprocess routine doesn’t return expected value! The expected value is imgurl, which is in src that I removed. It seems that the second for loop (for (var p=0; p< imgarr.length; p++){) doesn’t run at all, but the first one is OK. How do I fix this?

P.S.: I tried passing callback like this: xhr.onreadystatechange = function(imgprocess) {
but it doesnt work. It says “uncaught typeerror” object is not a function.

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1 Answer

  1. Editorial Team
     if (imgels[i].src.indexOf(parse(url)) != -1){
    imgarr = imgels[i];
 }

    it looks like you’re overwriting an array with a single element in the above code.

    Added edit:

    If the if condition is true, imgels[i] is an element (with an src) but instead of adding imgels[i] to the imgarr array, you are changing imgarr to point to a single element.

    Then in the second for loop, you are treating it as an array.

    In fact, this is also a mistake in the second loop. Is imgarres supposed to be an array or not? If it is then imgarres = imgarr[p]; is wrong (it points to an element after you do that). If it isn’t then var z = imgarres[0].src; is wrong (if it is an element you don’t need the [0]).

    Added edit:

    somearray = someelement;

    does not add the element to the array!

    somearray.push(someelement);

    does.

    Added edit: just try this instead. Who knows, it might work…

    function imgprocess(text){
 // get all IMG elements below the div
 imgels = text.getElementsByTagName("IMG");
 // filter them somehow
 imgarr = [];
 for (var i=0;i< imgels.length;i++){
   if (imgels[i].src.indexOf(parse(url)) != -1){
    imgarr.push(imgels[i]);
   }
 }

 // filter again, could probably be joined into one loop
 imgarres = [];
 for (var p=0; p< imgarr.length; p++){
   if (imgarr[p].parentNode.nodeName=="A"){
     imgarres.push(imgarr[p]);
   }
 }
 // return the first image's src if any
 if (imgarres.length > 0) {
   return imgarres[0].src;
 }
 return null;
}
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