var stepsize     = 0.05   ; /* one = full */
var steptime     = 50    ; /* time between steps */
var holdtime     = 4500  ; /* Time image stays 'on' in msecs */
var amountimages = 4      ; /* Amount of images to rotate through */

function slideout(step, objectnr) {
  step =  step - stepsize;

  //do iex
  document.getElementById( 'slider' + objectnr ).style.filter = "alpha(opacity=" + ( step * 100 ) + ");";
  //Do other browsers
  document.getElementById( 'slider' + objectnr ).style.opacity = step;

  if ( step < 0.03  ) {
    //do iex
    document.getElementById( 'slider' + objectnr ).style.filter = "alpha(opacity=" + 0 + ");";
    //Do other browsers
    document.getElementById( 'slider' + objectnr ).style.opacity = 0 ;

    if( objectnr == 2 ) {
      setTimeout( "slidein( " + 0 + ", '" +  ( objectnr ) + "' )", holdtime );
    }
    else {
      setTimeout( "slideout( " + 1 + ", '" +  ( --objectnr ) + "' )", holdtime );
    }

  }
  else {
    setTimeout( "slideout( " + step + ", '" +  objectnr + "' )", steptime )  ;
  }

}

function slidein( step, objectnr) {
  step =  step + stepsize  ;

  //do iex
  document.getElementById( 'slider' + objectnr ).style.filter = "alpha(opacity=" + ( step * 100 ) + ");";
  //Do other browsers
  document.getElementById( 'slider' + objectnr ).style.opacity = step;

  if (step > 0.98) {
    //do iex
    document.getElementById( 'slider' + objectnr ).style.filter = "alpha(opacity=" + 100 + ");";
    //Do other browsers
    document.getElementById( 'slider' + objectnr ).style.opacity = 1 ;

    if(objectnr == amountimages) {
      setTimeout( "slideout( " + 1 + ", '" +  ( objectnr ) + "' )", holdtime )  ;
    }
    else {
      setTimeout( "slidein( " + 0 + ", '" +  ( ++objectnr ) + "' )", holdtime )  ;
    }

  }
  else {
    setTimeout( "slidein( " + step + ", '" +  objectnr + "' )", steptime )  ;
  }

}