var nbannieres=875,currentbanniere=0, defautbanniere="m872_1200x230.jpg"

function bann_gcd(a, b) {
	var x=Math.abs(a), y=Math.abs(b), u
	while(y!=0) {
		u=y
		y = x%y
		x=u
	}
	return x
}

var BannDecal=7
var idChgBann=null, pauseDiapo=10000, dureeDiapo=1, nodiapo=0;

function Bann2009B() {
	var imn="mouette_250x188.jpg" 
//"mouette_400x300.jpg" //"Goeland2SiamBrest_400x300.jpg"; //"LaRocheAuxFees_400x300.jpg"; //"basPloumanachp7218278_400x300.jpg"
        document.write('<center><img border="0" src="http://jm.davalan.org/bann/'+imn+'" width="250" height="188" title="nouvel envol" alt="une mouette"></center>');
        document.write('<!-- Bannière Bas -->');
}

function namebann(n) {
        var a = ""+(n+1)+"_"
        while(a.length<4) a = "0"+a
        return "m"+a+"1200x" + ((n<282)?"200" : "230") +".jpg"
}


function Bann2009() {

for(BannDecal=Math.floor(Math.sqrt(nbannieres)+10*Math.random()); bann_gcd(nbannieres,BannDecal)!=1; BannDecal++);

currentbanniere = Math.floor(nbannieres*Math.random())
//currentbanniere=730
defautbanniere=namebann(currentbanniere)


var u= namebann(currentbanniere)
var s = '<div id="banniereduhaut" onclick="clicBann();"  style="cursor:pointer;height:200px;background:#ffffff url(http://jm.davalan.org/bann/'+defautbanniere+') no-repeat fixed top;"><img border="0" id="jeux-et-mathematiques" src="http://jm.davalan.org/bann/j-et-m_RougeTrans400x200.png" width="400" height="200" alt="J et M"></div>' +
'\n<!-- Bannière 2009 -->'
// alert(s)
document.write(s)
}

function bann(s) {
Bann2009()
if(idChgBann != null) {
	clearInterval(idChgBann);
}
idChgBann=setInterval("chgeBann();",100000);
return;
}

function clicBann() {
//BannDecal=1
if(idChgBann != null) {
        clearInterval(idChgBann);
}
	chgeBann()
	// dÃsactive le diaporama avec //
	//idChgBann=setInterval("chgeBann();",pauseDiapo);
	nodiapo=0
}

function chgeBann() {
	if(nodiapo<dureeDiapo) {
	currentbanniere = (currentbanniere+BannDecal)% nbannieres
	var u= namebann(currentbanniere);
	document.getElementById("banniereduhaut").style.background = '#ffffff url(http://jm.davalan.org/bann/'+u+') no-repeat fixed top'
	nodiapo++
	} else {
		if(idChgBann!=null) clearInterval(idChgBann);
		nodiapo=0
	}
}

function bann2(s) {
Bann2009B()
return
}