<!-- element manipulation -->    
var ns4 = document.layers;
var op5 = (navigator.userAgent.indexOf("Opera 5")!=-1) 
    ||(navigator.userAgent.indexOf("Opera/5")!=-1);
var op6 = (navigator.userAgent.indexOf("Opera 6")!=-1) 
    ||(navigator.userAgent.indexOf("Opera/6")!=-1);
var agt=navigator.userAgent.toLowerCase();
var mac = (agt.indexOf("mac")!=-1);
var ie = (agt.indexOf("msie") != -1); 
var mac_ie = mac && ie;

function getObjNN4(obj,name)
{
    var x = obj.layers;
    var foundLayer;
    for (var i=0;i<x.length;i++)
    {
        if (x[i].id == name)
            foundLayer = x[i];
        else if (x[i].layers.length)
            var tmp = getObjNN4(x[i],name);
        if (tmp) foundLayer = tmp;
    }
    return foundLayer;
}       

function getObject(objectId) {
    if(document.getElementById && document.getElementById(objectId)) {
        return document.getElementById(objectId);
    } else if (document.all && document.all(objectId)) {
        return document.all(objectId);
    } else if (document.layers && document.layers[objectId]) {
        return getObjNN4(document,objectId);
    } else {
        return false;
    }
}             

function getStyleObject(objectId) {
    if(document.getElementById && document.getElementById(objectId)) {
        return document.getElementById(objectId).style;
    } else if (document.all && document.all(objectId)) {
        return document.all(objectId).style;
    } else if (document.layers && document.layers[objectId]) {
        return getObjNN4(document,objectId);
    } else {
        return false;
    }
} 
    
function changeObjectDisplay(objectId, newDisplay) {
    var styleObject = getStyleObject(objectId, document);
    if(styleObject) {
        styleObject.display = newDisplay;
        return true;
    } else {
        return false;
    }
} 
   
function changeObjectVisibility(objectId, newVisibility) {
    var styleObject = getStyleObject(objectId, document);
    if(styleObject) {
        styleObject.visibility = newVisibility;
        return true;
    } else {
        return false;
    }
} 
   
function changeClass(objectId, newClass) {
    var elem;
    
    if(document.getElementById && document.getElementById(objectId)) {
        elem = document.getElementById(objectId);
    } else if (document.all && document.all(objectId)) {
        elem = document.all(objectId);
    } else if (document.layers && document.layers[objectId]) {
        elem = getObjNN4(document,objectId);
    } else {
        return false;
    }

    elem.className = newClass;
    return true;
}