function check_email(email) {
        b = true;
        if (email.lastIndexOf('@') < 1)
            b = false;
        if (email.lastIndexOf('@') > email.lastIndexOf('.'))
            b = false;
        if (email.lastIndexOf('@') == email.lastIndexOf('.')+1)
            b = false;
        if (email.length-email.lastIndexOf('.') < 3 || email.length-email.lastIndexOf('.') > 5)
            b = false;
        if (email.length<6)
            b = false;
        return(b);
    }

var nb_diapo = null;
var duree_transition = 1000;
var duree_suivante = 5000;

var num_diapo_old = null;
var num_mini_old = null;
var t_suivante=null;
var t_transition=null;
var en_transition=false;

function fin_transition(){
      en_transition=false;
}

function affDiapo(num_diapo){
  if(!en_transition && num_diapo != num_diapo_old){
    en_transition = true;
    if(t_suivante != null)
      clearInterval(t_suivante);
    if(t_transition != null)
      clearInterval(t_transition);

    if(num_diapo_old != null)
      opacity('diapo_zoom_'+num_diapo_old, 100, 0, duree_transition);
    opacity('diapo_zoom_'+num_diapo, 0, 100, duree_transition);
    t_transition = setInterval('fin_transition()', duree_transition);

    num_diapo_old = num_diapo;
    affMini(num_diapo);

    t_suivante = setInterval('diapoSuivante()', duree_suivante);
  }
}

function affMini(num_mini){
  for(var i=0; i<=nb_diapo+1; i++){
    if(i>=num_mini-1 && i<=num_mini+1){
      document.getElementById('diapo_mini_'+i).style.display='block';
      if((i-1+nb_diapo)%nb_diapo == num_diapo_old-1)
        document.getElementById('diapo_mini_'+i).className = 'diapo_active';
      else
        document.getElementById('diapo_mini_'+i).className = '';
    }
    else
      document.getElementById('diapo_mini_'+i).style.display='none';
  }
  num_mini_old = num_mini;
}


function diapoSuivante(){
  if(num_diapo_old != null){
    num_diapo = num_diapo_old+1;
    if(num_diapo>nb_diapo)
      num_diapo=1;
    affDiapo(num_diapo);
  }
}

function miniSuivante(){
  if(num_mini_old != null){
    if(t_suivante != null)
      clearInterval(t_suivante);
    num_mini = num_mini_old+1;
    if(num_mini>nb_diapo)
      num_mini=1;
    affMini(num_mini);
    t_suivante = setInterval('diapoSuivante()', duree_suivante);
  }
}

function miniPrecedente(){
  if(num_mini_old != null){
    if(t_suivante != null)
      clearInterval(t_suivante);
    num_mini = num_mini_old-1;
    if(num_mini<1)
      num_mini=nb_diapo;
    affMini(num_mini);
    t_suivante = setInterval('diapoSuivante()', duree_suivante);
  }
}



function opacity(id, opacStart, opacEnd, millisec) {
    //speed for each frame
    var speed = Math.round(millisec / 100);
    var timer = 0;

    //determine the direction for the blending, if start and end are the same nothing happens
    if(opacStart > opacEnd) {
        for(i = opacStart; i >= opacEnd; i--) {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    } else if(opacStart < opacEnd) {
        for(i = opacStart; i <= opacEnd; i++)
            {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    }
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
    var object = document.getElementById(id).style; 
    object.opacity = (opacity / 100);
    object.MozOpacity = (opacity / 100);
    object.KhtmlOpacity = (opacity / 100);
    object.filter = "alpha(opacity=" + opacity + ")";
}