function opacity(id, opacStart, opacEnd, millisec) { 

   var speed = Math.round(millisec / 100);
   var timer = 0; 

   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++; 
      } 
   }
} 

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 + ")"; 
    if(object.opacity == 0){
       object.display = 'none';
    }else{
       object.display = 'block';
    }
}

function shiftOpacity(id, millisec) { 
    if(document.getElementById(id).style.opacity == 0) {
        opacity(id, 0, 100, millisec);
    } else { 
        opacity(id, 100, 0, millisec); 
    } 
}

function fader(id, start, end, time){
   opacity(id, start, end, time);
}