function popup_open(n){
    var img = document.getElementById("popup_img");
    var loading = document.getElementById("loading_div");
    img.style.visibility = "hidden";
    img.src = n;
    loading.style.visibility = "visible";
    img.onload=function () { initImage(img); }
}

function popup_close(){
    var img = document.getElementById("popup_img");
    var loading = document.getElementById("loading_div");
    img.style.visibility = "hidden";
    loading.style.visibility = "hidden";
}

function initImage(image) {
    setOpacity(image, 0);
    image.style.visibility = 'visible';
    fadeIn(image,0);
}

function setOpacity(obj, opacity) {
    opacity = (opacity == 100)?99.999:opacity;
  
    // IE/Win
    // obj.style.filter = "alpha(opacity:"+opacity+")";
  
    // Safari<1.2, Konqueror
    obj.style.KHTMLOpacity = opacity/100;
  
    // Older Mozilla and Firefox
    obj.style.MozOpacity = opacity/100;
  
    // Safari 1.2, newer Firefox and Mozilla, CSS3
    obj.style.opacity = opacity/100;
}

function fadeIn(img,opacity) {
    if (opacity <= 100) {
        setOpacity(img, opacity);
        opacity += 10;
        setTimeout(function () { fadeIn(img, opacity) }, 25);
    }
}