// Ajax post
function xml_httpPost(strURL, querystring, ret_func)
{
    var xmlHttpReq = false;
    var self = this;
    // Mozilla/Safari
    if (window.XMLHttpRequest) {
        self.xmlHttpReq = new XMLHttpRequest();
    }
    // IE
    else if (window.ActiveXObject) {
        self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
    } else {
        alert ("Can`t send request! Your browser don`t support XMLRequest");
        return false;
    }

    self.xmlHttpReq.open('POST', strURL, true);
    self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    self.xmlHttpReq.onreadystatechange = function() {
        if (self.xmlHttpReq.readyState == 4) {
            if (ret_func) {
                ret_func(self.xmlHttpReq.responseText, self.xmlHttpReq.responseXML);
            }
        }
    }
    self.xmlHttpReq.send( querystring );
}

function addEvent (el, evname, func)
{
    if (el.attachEvent) { // IE
        el.attachEvent("on" + evname, func);
    } else if (el.addEventListener) { // Gecko / W3C
        el.addEventListener(evname, func, true);
    } else {
        el["on" + evname] = func;
    }
}

function removeEvent (el, evname, func)
{
    if (el.detachEvent) { // IE
        el.detachEvent("on" + evname, func);
    } else if (el.removeEventListener) { // Gecko / W3C
        el.removeEventListener(evname, func, true);
    } else {
        el["on" + evname] = null;
    }
}

function preload_img()
{ 
   var img_list = preload_img.arguments;
   if (document.preloadlist == null) 
       document.preloadlist = new Array();
   var top = document.preloadlist.length;
   for (var i=0; i < img_list.length; i++) {
       document.preloadlist[top+i] = new Image;
       document.preloadlist[top+i].src = 'http://bitrar.com/images/'+img_list[i+1];
   } 
}

function load_all()
{
    preload_img('head2_1.jpg','head2_2.jpg','head2_3.jpg','head2_4.jpg','head2_5.jpg','head2_6.jpg','head2_7.jpg','head2_8.jpg','head2_9.jpg');
}

function changeLogo( num )
{
    document.getElementsByName('img_logo')[0].src = '/images/head2_'+num+'.jpg';
    return false;
}

function scroll_left()
{
    var elem = document.getElementById('screens_maindiv');

    if (current>1)
    {
        val++;
        var step = (val==23) ? 5 : 6;
        elem.style.left = String(Number(elem.style.left.substring(0, elem.style.left.length - 2)) + step) + 'px';
        if (val<23) setTimeout('scroll_left()', 3);
        else { val = 0; current--; }
    }
}

function scroll_right() 
{
    var elem = document.getElementById('screens_maindiv');

    if ((current+shown-1)<total)
    {
        val++;
        var step = (val==23) ? 5 : 6;
        elem.style.left = String(Number(elem.style.left.substring(0, elem.style.left.length - 2)) - step) + 'px';
        if (val<23) setTimeout('scroll_right()', 3);
        else { val = 0; current++; }
    }
}

var val     = 0;
var total   = 9;
var shown   = 5;
var current = 1;