var NewsSliderFixWidth = 535;
var NewsOffsetFixWidth = 0;
var NewsNavigator;
var xmlhttp;

function SlideNewsToLeft(sld)
{
    if(sld != null)
    {
        if ((sld.offsetWidth + sld.offsetLeft) > NewsSliderFixWidth)
        {
            var _left = sld.offsetLeft - NewsSliderFixWidth;
            
            if ((sld.offsetWidth + _left) < NewsSliderFixWidth)
                _left = -(sld.offsetWidth - NewsSliderFixWidth);

            SlideNews(sld, -1, sld.offsetLeft, _left);
        }
    }
}


function SlideNewsToRight(sld)
{
    if(sld != null)
    {
        var _left = 0;
        if (sld.offsetLeft < 0)
            _left = (sld.offsetLeft + NewsSliderFixWidth);

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


function SlideNews(sld, direction, currentPosition, NewPosition)
{
    var slideOffset = 50 * direction;
    currentPosition += slideOffset;
    if ( ((direction == -1) && (currentPosition < NewPosition)) ||
         ((direction == +1) && (currentPosition > NewPosition)) )
            currentPosition = NewPosition;
    sld.style.left = currentPosition + 'px';
    if (currentPosition != NewPosition)
        setTimeout(function(){SlideNews(sld, direction, 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();
        if (xmlhttp.overrideMimeType) 
            xmlhttp.overrideMimeType('text/xml');
    }
    // codice per  IExplore
    else if (window.ActiveXObject)
    {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
    }

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

function xmlhttpChange(target)
{
    //alert(xmlhttp.readyState);
    // 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('divReadNewsContent');
            ToogleDisplayElement(target);

            SlideNewsReader(element);

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


function SlideNewsReader(sld)
{
    if(sld != null)
    {
        sld.style.left = NewsSliderFixWidth + 'px';
        SlideNews(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 (NewsNavigator)
    {
        NewsNavigator.style.visibility = 'visible';
    }
}


function InitNewsNavigator(id)
{
    NewsNavigator = document.getElementById(id);
}