doAjaxStuff

Pra eu não ter mais que ficar procurando essa função:

function doAjaxStuff
    (postQueryString, onreadystatechange, action)
{
    try 
    {
        // Firefox, Opera 8.0+, Safari
        xmlHttp=new XMLHttpRequest();
    }
    catch (e)
    {
        // Internet Explorer 
        try 
        { 
            xmlHttp=new ActiveXObject("Msxml2.XMLHTTP"); 
        } 
        catch (e) 
        { 
            try 
            {
                xmlHttp=new ActiveXObject
                   ("Microsoft.XMLHTTP"); 
            }
            catch (e)
            {
                alert("Seu navegador não suporta AJAX!");
                return false;
            }
        }
    }
    xmlHttp.onreadystatechange=onreadystatechange;
    xmlHttp.open("POST", action, true);
    xmlHttp.setRequestHeader
        ("Content-type", "application/x-www-form-urlencoded");
    xmlHttp.setRequestHeader
        ("Content-length", postQueryString.length);
    xmlHttp.setRequestHeader("Connection", "close");
    xmlHttp.send(postQueryString);
}