function fade(step) {
    var imgs = document.getElementById("content").getElementsByTagName("img");

    step = step || 0;

    imgs[counter].style.opacity = step/100;
    imgs[counter].style.filter = "alpha(opacity=" + step + ")"; // 

    step = step + 1.5;

    if (step <= 100) {
      window.setTimeout(function () { fade(step); }, 1);
    }
  }
        
  function startSlide(){
    window.setTimeout(next, 1000);
  }
  
  function next() {
    var imgs = document.getElementById("content").getElementsByTagName("img");
    
    if (typeof(counter) != "number") {
      counter = 0;
    }

    counter++;

    if (counter < imgs.length) {
      fade();
    }
  };