var picturesSlide=new Array("images/slide0.jpg","images/slide6.jpg","images/slide1.jpg","images/slide2.jpg","images/slide3.jpg","images/slide4.jpg","images/slide5.jpg");
var loadSlide=2;
var lastSilde=7;
var strLanguage;


function shiftOpacity(id, millisec) {
    //if an element is invisible, make it visible, else make it ivisible
	//alert (document.getElementById(id).style.opacity);
    if(document.getElementById(id).style.opacity == 0) {
		//alert (99);
		opacity(id, 0, 100, millisec);	
    } else {
		opacity(id, 100, 0, millisec);
    }
	setTimeout("shiftPictures('" + id + "', " + millisec + ")", 2000);
	
} 

function shiftPictures(id, millisec) {

	loadSlide++;
	if(loadSlide>lastSilde) {loadSlide=0;}

    //if an element is invisible, make it visible, else make it ivisible



    if(document.getElementById(id).style.opacity == 0) {
		//ustaw tlo
		document.getElementById(id).src = "images/slide" + strLanguage + loadSlide + ".jpg";
    } else {
		//usaw obrazek
		document.getElementById("slidediv").style.backgroundImage = "url(images/slide" + strLanguage + loadSlide  + ".jpg)";
    }
	setTimeout("shiftOpacity('" + id + "', " + millisec + ")", 4000);

	
}

function opacity(id, opacStart, opacEnd, millisec) {
    //speed for each frame
    var speed = Math.round(millisec / 100);
    var timer = 0;

    //determine the direction for the blending, if start and end are the same nothing happens
    if(opacStart > opacEnd) {
        for(i = opacStart; i >= opacEnd; i--) {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    } else if(opacStart < opacEnd) {
        for(i = opacStart; i <= opacEnd; i++)
            {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    }
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
    var object = document.getElementById(id).style;
    object.opacity = (opacity / 100);
    object.MozOpacity = (opacity / 100);
    object.KhtmlOpacity = (opacity / 100);
    object.filter = "alpha(opacity=" + opacity + ")";
} 

function StartShiftOpacity(id, millisec) {
	var randomnumber=Math.floor(Math.random()*(lastSilde+1));
	strLanguage = document.getElementById("L").value;
	//alert(document.getElementById("L").value);
	loadSlide = randomnumber;
	//document.getElementById(id).style.opacity = 0;
	//document.getElementById("slidediv").style.backgroundImage = "url(images/slide1.jpg)";
	
	changeOpac(0, id);
	document.getElementById(id).src = "images/slide" + strLanguage + loadSlide  + ".jpg";

	setTimeout("shiftOpacity('" + id + "', " + millisec + ")", 100);
	//setTimeout("shiftOpacity('blendimage', 700)", 5000);
	
}