var PageBooksSliderFixWidth = 0; //535;
var PageBooksOffsetFixWidth = 0;
var PageBooksSliderFixHeight = 0; //296;
var PageBooksOffsetFixHeight = 0;
var PageBooksNavigator;
var xmlhttp;


function SlidePageBooksToLeft(sld, w)
{
    PageBooksSliderFixWidth = w;
    if(sld != null)
    {
        if ((sld.offsetWidth + sld.offsetLeft) > PageBooksSliderFixWidth)
        {
            var _left = sld.offsetLeft - PageBooksSliderFixWidth;
            
            if ((sld.offsetWidth + _left) < PageBooksSliderFixWidth)
                _left = -(sld.offsetWidth - PageBooksSliderFixWidth);

            SlidePageBooks(sld, -1, 0, sld.offsetLeft, _left);
        }
    }
}


function SlidePageBooksToRight(sld, w)
{
    PageBooksSliderFixWidth = w;
    if(sld != null)
    {
        var _left = 0;
        if (sld.offsetLeft < 0)
            _left = (sld.offsetLeft + PageBooksSliderFixWidth);

        if (_left > 0) _left = 0;
        
        SlidePageBooks(sld, +1, 0, sld.offsetLeft, _left);
    }
}


function SlidePageBooksToUp(sld, h)
{
    PageBooksSliderFixHeight = h;
    if(sld != null)
    {
        if ((sld.offsetHeight + sld.offsetTop) > PageBooksSliderFixHeight)
        {
            var _top = sld.offsetTop - PageBooksSliderFixHeight;
            
            if ((sld.offsetHeight + _top) < PageBooksSliderFixHeight)
                _top = -(sld.offsetHeight - PageBooksSliderFixHeight);

            SlidePageBooks(sld, -1, 1, sld.offsetTop, _top);
        }
    }
}


function SlidePageBooksToDown(sld, h)
{
    PageBooksSliderFixHeight = h;
    if(sld != null)
    {
        var _top = 0;
        if (sld.offsetTop < 0)
            _top = (sld.offsetTop + PageBooksSliderFixHeight);

        if (_top > 0) _top = 0;
        
        SlidePageBooks(sld, +1, 1, sld.offsetTop, _top);
    }
}


function SlidePageBooks(sld, direction, scroll, currentPosition, NewPosition)
{
    var slideOffset = 50 * direction;
    currentPosition += slideOffset;
    if ( ((direction == -1) && (currentPosition < NewPosition)) ||
         ((direction == +1) && (currentPosition > NewPosition)) )
            currentPosition = NewPosition;
    //alert(currentPosition);
    if (scroll == 0)
        sld.style.left = currentPosition + 'px';
    else
        sld.style.top = currentPosition + 'px';
    if (currentPosition != NewPosition)
        setTimeout(function(){SlidePageBooks(sld, direction, scroll, currentPosition, NewPosition)}, 10);
 }  


function DoPostCallBack(url, target)
{
    DoCallBack(url, "POST", target);
}
    
function DoGetCallBack(url, target)
{
    DoCallBack(url, "GET", target);
}
    
function DoCallBack(url, method, target)
{
    // codice per Mozilla, etc.
    if (window.XMLHttpRequest)
    {
        xmlhttp = new XMLHttpRequest();
     }
    // codice per  IExplore
    else if (window.ActiveXObject)
    {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }

    if (xmlhttp)
    {
        xmlhttp.onreadystatechange = function() {xmlhttpChange(target);};
        xmlhttp.open(method, url, false);
        xmlhttp.send(null);
    }
    return xmlhttp;
}

function xmlhttpChange(target)
{
    // if xmlhttp shows "loaded"
    if (xmlhttp.readyState == 4)
    {
        // if "OK"
        if (xmlhttp.status == 200)
        {
            var element;

            element = document.getElementById(target);
            element.innerHTML  = xmlhttp.responseText;
            
            ToogleDisplayElement('divReadPageBooksContent');
            ToogleDisplayElement(target);

            SlidePageBooksReader(element);

            if (PageBooksNavigator)
            {
                PageBooksNavigator.style.visibility = 'hidden';
            }
        }
        else
        {
            alert("Impossibile ricevere i dati");
        }
    }
}


function SlidePageBooksReader(sld)
{
    if(sld != null)
    {
        sld.style.left = PageBooksSliderFixWidth + 'px';
        SlidePageBooks(sld, -1, sld.offsetLeft, 0);
    }
}


function ToogleDisplayElement(id)
{
    var element;
    
    element = document.getElementById(id);
    element.style.display = ((element.style.display == 'none') ? 'block' : 'none');
}


function ToogleElement(div1, div2)
{
    var element;
    
    element = document.getElementById(div1);
    element.style.display = ((element.style.display == 'none') ? 'block' : 'none');

    element = document.getElementById(div2);
    element.style.display = ((element.style.display == 'none') ? 'block' : 'none');
    
    if (PageBooksNavigator)
    {
        PageBooksNavigator.style.visibility = 'visible';
    }
}


function InitPageBooksNavigator(id)
{
    PageBooksNavigator = document.getElementById(id);
}