function ajax(){
try{
    xmlhttp = new XMLHttpRequest();
}catch(ee){
    try{
        xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    }catch(e){
        try{
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        }catch(E){
            xmlhttp = false;
        }
    }
}
}

function AjaxDinamico(NomeDiv, Pagina, Mensagem){
var conversa = document.getElementById(""+NomeDiv+"")
conversa.innerHTML  = Mensagem;

ajax()
xmlhttp.open("GET", Pagina,true);
xmlhttp.onreadystatechange=function() {
    if (xmlhttp.readyState == 4){
    	xmlhttp.setRequestHeader( "Content-Type","text/html; charset=iso-8859-1" );
    	var texto_retorno   = xmlhttp.responseText
		conversa.innerHTML  = texto_retorno;
  }
}
xmlhttp.send(null);
}