currentImage = getNumImage();

$(document).ready(function() {
	afficheImage();
	
	$("#recule").click(function() {
		recule();
	});
	$("#avance").click(function() {
		avance();
	});
	
	$(document).keypress(function(e) {
		if((e.keyCode == 37) || (e.keyCode == 38)) {
			recule();
		} else {
			avance();
		}
	});
	
	prechargeImageSuivante();
});

function avance() {
	currentImage = currentImage + 1;

	if(currentImage == 57) {
		window.location.replace("fin.html");
	} else {
		afficheImage();
//		href = window.location.href;
//		egalePos = href.indexOf('=');
//		window.location.href = href.substring(0, egalePos+1) + currentImage; 
	}
}

function getNumImage() {
	href = window.location.href;
	egalePos = href.indexOf('=');
	return parseInt(href.substring(egalePos+1, href.length));	
}

function recule() {
	currentImage = currentImage - 1;
	if(currentImage == 1) {
		window.location.replace("index.html");
	} else {
		afficheImage();
	}
}

function afficheImage() {
	var image = $("#image")
	image.fadeTo('normal', 0.1 , function(){
		image.attr("src", getNomImage(currentImage));
		image.fadeTo('normal', 1);
		prechargeImageSuivante();
	});
}

function getNomImage(imageNum) {
	return "images/page" + imageNum + ".jpg?lastmod=1112";
}

function prechargeImageSuivante() {
	var nextImage = new Image();
	$(nextImage).attr('src', getNomImage(currentImage+1));	
}