var imageURL;
var doUpdates = false;

function updateButton()
{
    var button = document.getElementById("refreshBtn");

    if (! button) {
        return;
    }

    if (doUpdates) {
        button.value = "Stop updates";
        button.onclick = stopUpdates;
    }
    else {
        button.value = "Auto-refresh";
        button.onclick = startUpdates;
    }
}

function startUpdates()
{
    doUpdates = true;
    updateButton();

    grabImage();
}

function stopUpdates()
{
    doUpdates = false;
    updateButton();
}

function grabImage()
{
    imageURL = "http://139.229.12.16:8888/video/frame?" +
            (new Date()).getTime();

    var img = new Image();
    img.src = imageURL;
    img.onload = replaceImage;
}

function replaceImage()
{
    var promptcam = document.getElementById("promptcam");
    promptcam.src = imageURL;

    if (doUpdates) {
        setTimeout("grabImage();", 600);
    }
}

function openMiniWindow(evt)
{
    var e = evt || event;

    window.open ("mini.html", "minipromptcam",
                 "menubar=0,status=0,width=350,height=270"); 

    stopUpdates();

    e.returnValue = false;
    if (e.preventDefault) {
        e.preventDefault();
    }
    return false;
}