var request;
var rat;

function do_request() {
    if (window.ActiveXObject) {
        request = new ActiveXObject("Microsoft.XMLHTTP");
    }
    else {
        request = new XMLHttpRequest();
    }
}


function rating(rating, id, type) {
    rat = rating;
    var url = "./ajax/rating.php?id=" + id + "&rating=" + rating + "&type=" + type;
    
    do_request();
    request.onreadystatechange = get_data;
    request.open("GET", url);
    request.send(null);
}

function get_data() {
    if (request.readyState == 4) {
        var rating = request.responseText;
    
        if (rating == 'ok') {
            var area = document.getElementById("rating_area");
            area.innerHTML = "";
            
            var i;
            for (i = 1; i <= rat; i++) {
                area.innerHTML += '<img src="grafika/star_active.png" />';
            }
        
            for (i = rat; i < 5; i++) {
                area.innerHTML += '<img src="grafika/star.png" />';
            }    
        
            area.innerHTML += "<br /><b>Děkujeme za hodnocení !</b>";
        }
        if (rating == 'del') {
            var area = document.getElementById("rating_area");
            area.innerHTML = "";
        
            area.innerHTML += "<br /><b>Hodnocení bylo smazáno</b>";
        }
    }
}


function over(el) {
    var i;
    var elem;

    elem = document.getElementById("rating0");
    elem.src = "grafika/thumb_active.png";
    for (i = 1; i <= el; i++) {
        elem = document.getElementById("rating" + i);
        elem.src = "grafika/star_active.png";
    }
}

function out() {
    var i;
    var el;
    
    elem = document.getElementById("rating0");
    elem.src = "grafika/thumb.png";
    for (i = 1; i <= 5; i++) {
        el = document.getElementById("rating" + i);
        el.src = "grafika/star.png";
    }
}

//funkce pro zobrazeni a skryti vice obalu knih
function show_covers(id, num) {
    var div = document.getElementById("covers");
    
    //vlozeni obalu knih
    div.innerHTML = '<img src="img.php?type=book&size=book_detail&id=' + id + '" alt="Obal knihy" /> ';
    for (var i = 1; i < num; i++) {
        div.innerHTML += '<img src="img.php?type=book&size=book_detail&id=' + id + '_' + i + '" alt="Obal knihy" /> ';    
    }
    
    div.innerHTML += "<br /><br />";
    div.style.display = "block";
}

function hide_covers() {
    var div = document.getElementById("covers");
    div.style.display = "none";    
}