Kako u JavaScript-u da pokupim getElementById(id) iz XMLHttpRequest?

Code:

function AjaxLoad(p_elements, p_url)
{
    xmlhttp = CreateHTTPRequestObject()
    xmlhttp.onreadystatechange=function()
    {
        if (xmlhttp.readyState==4 && xmlhttp.status==200)
        {
            var  element_array = p_elements.split(",");
            for(int i = 0; i < element_array.length; i++)
            {
              var element = document.getElementById(element_array[i]);
              if(element != null)
              {
                requestElemement = xmlhttp.getElementById(element_array[i]);//<<<<<<<< kako ovo izvesti?
                if(requestElemement != null)
                {
                    element.innerHTML = requestElemement.innerHTML;
                }
            }
        }
    }
    xmlhttp.open("GET", p_url, true);
    xmlhttp.send();
}

function CreateHTTPRequestObject()
{
    if (window.XMLHttpRequest)
    {// code for IE7+, Firefox, Chrome, Opera, Safari
        return new XMLHttpRequest();
    }
    else
    {// code for IE6, IE5XMLHttpRequest
        return new ActiveXObject("Microsoft.XMLHTTP");
    }
}