var imagewidth = 80;
var imageheight = 101;
var imagespeed = 1;
var xmax;
var ymax;
var xPos = 400;
var yPos = 0;
var xDir ='droite';
var yDir ='bas';
var newXDir;
var newYDir;

function moveimage()
{
	calculatePosition();
	document.getElementById("image").style.left = xPos;
	document.getElementById("image").style.top = yPos;
	setTimeout('moveimage()',120);
}
function initializeimage()
{
	if (document.all){
		xmax=document.body.clientWidth
		ymax=document.body.clientHeight
	}else{
		xmax=window.innerWidth;
		ymax=window.innerHeight;
	}
	setTimeout('moveimage()',400);
}

function calculatePosition()
{
	if (xDir == "droite"){
		if (xPos > (790 - imagewidth - imagespeed)){
			xDir = "gauche";
			}
		}
	else if (xDir == "gauche"){
		if (xPos < (10 + imagespeed)){
			xDir = "droite";
			}
		}
	if (yDir == "bas"){
		if (yPos > (450 - imageheight - imagespeed)){
			yDir = "haut";
			}
		}
	else if (yDir == "haut"){
		if (yPos < (0 + imagespeed)){
			yDir = "bas";
			}
		}
	if (xDir == "droite"){
		xPos = xPos + imagespeed;
		}
	else if (xDir == "gauche"){
		xPos = xPos - imagespeed;
		}
	else {
		xPos = xPos;
		}
	if (yDir == "bas"){
		yPos = yPos + imagespeed;
		}
	else if (yDir == "haut"){
		yPos=yPos - imagespeed;
		}
	else {
		yPos = yPos;
		}
}