function dialog(content, width, height, border) {
    /**
    * @param content: html/JS kod, ktery se vykona uvnitr objektu "dialog", napr. <img src=..>
    * @param width and height: rozmery obr.
    * @param border: tloustka ohraniceni DIVu v px     
    */
       
    // "zneaktivneni" pozadi
    object_bg = document.createElement("div");
    object_bg.id = "bg_off";
    object_bg.onclick = function () {CloseDialog()}; // IE neumi pres setAttribute aplikovat onclick, proto tohle reseni
    document.body.appendChild(object_bg);
    
    // dialog window
    object = document.createElement("div");
    object.id = "dialog";
    object.style.width = width;
    object.style.height = height;
    object.style.marginLeft = - Math.round((width + border * 2) / 2); // zaokrouhlime na cele cislo
    object.style.marginTop = - Math.round((height + border * 2) / 2);
    object.innerHTML = content;
    document.body.appendChild(object);
}

function CloseDialog() {
    parent_object = document.getElementsByTagName("body")[0];
    child_bg = document.getElementById("bg_off");
    child_dialog = document.getElementById("dialog");
    parent_object.removeChild(child_bg);
    parent_object.removeChild(child_dialog);
}