var nbrand = 0;
function debut()
{
	chgimg();
}
nbdiapo = 25;
nod = 1;
old = 0;
var tab_d = Array();
cur=document.getElementById("imgaff");
var i ;
for (i = 1 ; i<= nbdiapo ; i++)
{
	tab_d[i] = 1;
}

tab_d[1] = 0 ;
tab_d[2] = 0;

function rand()
{
	return Math.ceil((Math.random()*nbdiapo));
}

function chgimg()
{
	n = rand();
	while(tab_d[n] == 0 && nod <= nbdiapo)
	{
		n = rand();
		nbrand++;
	}
	nod++;
	
	window.document.getElementById("prechg").src ="diapo/diapo"+n+".png";

	if(document.all) {
        if (window.document.getElementById("imgaff").filters.alpha.opacity <= 0 )
        {
                tab_d[n] = 0 ;
                window.document.getElementById("imgaff").src = "diapo/diapo"+old+".png";
                setTimeout("visible()",500);
        }
        else
        {
                window.document.getElementById("divimg").style.backgroundImage = 'url("diapo/diapo' + old + '.png")';
                setTimeout("invisible()",500);
        }
        }

	else {
	if (window.document.getElementById("imgaff").style.getPropertyValue("-moz-opacity") <= 0 )
	{
		tab_d[n] = 0 ;
		window.document.getElementById("imgaff").src = "diapo/diapo"+old+".png";
		setTimeout("visible()",1000);
	}
	else
	{
		window.document.getElementById("divimg").style.backgroundImage = 'url("diapo/diapo' + old + '.png")';
		setTimeout("invisible()",1000);
	}
	}
	old = n;
	
	if (nod >= nbdiapo)
	{
		
		for (i = 1 ; i<= nbdiapo ; i++)
		{
			tab_d[i] = 1;
		}
		nod = 0;
	}
	setTimeout("chgimg()",3000);
}
 
function visible(){

	 // defaut : 20
	 vitesseIE=5;
	 vitesseFF=60;
	 if(document.getElementById) {
		 cur=document.getElementById("imgaff");	
		 if(document.all){
			 cur.filters.alpha.opacity++;
			 if (cur.filters.alpha.opacity==100)
			 	return;
			 else
				 setTimeout("visible()",vitesseIE);
			
		 }
		 else{
			 i=parseFloat(cur.style.getPropertyValue("-moz-opacity"));
			 i+=parseFloat(0.1);
			 
			 cur.style.setProperty("-moz-opacity", i, "");
			 if (i>=1)
				 return;
			 else
				 setTimeout("visible()",vitesseFF);
		 }
	 }
 }
 
 function invisible(){

 // defaut : 20 
 vitesseIE=5;
 vitesseFF=60;
 if(document.getElementById) {
 cur=document.getElementById("imgaff");
 if(document.all){
 cur.filters.alpha.opacity--;
 
 if (cur.filters.alpha.opacity==0)
 return;
 else
 setTimeout("invisible()",vitesseIE);

 }
 else{
 
 i=parseFloat(cur.style.getPropertyValue("-moz-opacity"));
 i-=parseFloat(0.1);
 cur.style.setProperty("-moz-opacity", i, "");
 if (i<=0)
 return;
 else
 setTimeout("invisible()",vitesseFF);
 }
 }
 }