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+1; i >= opacEnd; i--) {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    } else if(opacStart < opacEnd) {
        for(i = opacStart+1; i <= opacEnd; i++)
            {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    }
    changeOpac(opacStart, id);
}

var safari = navigator.userAgent.indexOf('Safari')!=-1;
var opacity_ie5;
var opacity_ns6;
if (safari) {
  opacity_ie5 = false;
  opacity_ns6 = true;
}
else {
  opacity_ie5 = !safari && (document.all && document.getElementById);
  opacity_ns6 = (!document.all && document.getElementById);
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
    var object = document.getElementById(id).style;
    if (opacity_ns6) {
        object.MozOpacity = (opacity / 100);
    }
    else if (opacity_ie5) {
        object.filter = "alpha(opacity=" + opacity + ")";
    }
    else {
        object.opacity = (opacity / 100);
        object.KhtmlOpacity = (opacity / 100);
    }
}