var slideWidth = 560;
var j=0;
var m=0;
var t, l;
function createSlide()
{
for(var i=0; i<4; i++)
{
document.getElementById("slide"+(i+1)).style.left = eval(slideWidth*i) + "px";
}
document.getElementById("photo").style.position="relative";
document.getElementById("photo").style.display="block";
resetNextBack();
document.getElementById("nextBtn2").style.display = "none";
document.getElementById("backBtn2").style.display = "none";
}


function nextSlide()
{
document.getElementById("nextBtn1").style.display = "none";
document.getElementById("nextBtn2").style.display = "block";
for(var k=1; k<5; k++)
{
var myslide = document.getElementById("slide"+k).style.left;
var subst = myslide.substring(0,(myslide.length-2)) 
document.getElementById("slide"+k).style.left = eval(subst-20) +  "px";
}
j=j+20;
var mode = eval(j%slideWidth);
if(mode == 0)
{
clearTimeout(t);
resetNextBack();
document.getElementById("nextBtn1").style.display = "block";
document.getElementById("nextBtn2").style.display = "none";
}
}

function backSlide()
{
document.getElementById("backBtn1").style.display = "none";
document.getElementById("backBtn2").style.display = "block";
for(var k=1; k<5; k++)
{
var myslide = document.getElementById("slide"+k).style.left;
var subst = myslide.substring(0,(myslide.length-2)) 
document.getElementById("slide"+k).style.left = eval(subst-(-20)) +  "px";
}
m=m+20;
var mode1 = eval(m%slideWidth);
if(mode1 == 0)
{
clearTimeout(l);
resetNextBack();
document.getElementById("backBtn1").style.display = "block";
document.getElementById("backBtn2").style.display = "none";
}
}

function fade() 
{
	if(document.getElementById("slide3").style.left != "0px")
		{
		t = setInterval("nextSlide()",1); 
		}
}

function fade1() 
{
	if(document.getElementById("slide1").style.left != "0px")
	{
	l = setInterval("backSlide()",1);
	}	
}

function resetNextBack()
{
	if(document.getElementById("slide1").style.left == "0px")
	{
		document.getElementById("backBtn1").style.opacity = "0.5";
		document.getElementById("backBtn1").style.filter = "alpha(opacity=50)";	
		document.getElementById("nextBtn1").style.opacity = "1";
		document.getElementById("nextBtn1").style.filter = "alpha(opacity=100)";
	}
	else if(document.getElementById("slide3").style.left == "0px")
	{
	document.getElementById("backBtn1").style.opacity = "1";
	document.getElementById("backBtn1").style.filter = "alpha(opacity=100)";	
	document.getElementById("nextBtn1").style.opacity = "0.5";
	document.getElementById("nextBtn1").style.filter = "alpha(opacity=50)";
	}	
	else
	{
	document.getElementById("backBtn1").style.opacity = "1";
	document.getElementById("backBtn1").style.filter = "alpha(opacity=100)";	
	document.getElementById("nextBtn1").style.opacity = "1";
	document.getElementById("nextBtn1").style.filter = "alpha(opacity=100)";		
	}
}