var custCount = 0;

function animateCustomers(custId, opacity) {
  if (browser.isIE && browser.version < 7) {
    // no fade in / out effect
    opacity = 100;
    var prevCustId = custId - 1;
    if (prevCustId < 1) prevCustId = custCount;
    var prevCust = document.getElementById("cust" + prevCustId);
    prevCust.style.visibility = "hidden";
    var cust = document.getElementById("cust" + custId);
    cust.style.visibility = "visible";
    cust.style.opacity = opacity / 100;
    cust.style.filter = "alpha(opacity=" + opacity + ")";
    custId +=1;
    if (custId > custCount) custId = 1;    
    setTimeout(function() { animateCustomers(custId, opacity) }, 2500);
    return;
  }
  var interval = 10;
  opacity += 1;
  if (opacity <= 50) {
    var prevCustId = custId - 1;
    if (prevCustId < 1) prevCustId = custCount;
    var prevCust = document.getElementById("cust" + prevCustId);
    var prevOpacity = 50 - opacity;
    if (prevOpacity < 5) prevOpacity = 0;
    prevCust.style.opacity = prevOpacity / 100;
    prevCust.style.filter = "alpha(opacity=" + prevOpacity + ")";    
    prevCust.style.visibility = "visible";
  }
  if (opacity > 100) {
    opacity = 0;
    custId +=1;
    if (custId > custCount) custId = 1;
    interval = 2000;
  }
  var cust = document.getElementById("cust" + custId);
  cust.style.opacity = opacity / 100;
  cust.style.filter = "alpha(opacity=" + opacity + ")";
  cust.style.visibility = "visible";
  setTimeout(function() { animateCustomers(custId, opacity) }, interval);
}