ajax php rss reader

Sem se cisti zacetnik kar se tice ajax-a in php-ja in se mucim z prilagajanjem ene skripte http://www.w3schools.com/php/php_ajax_r...

Namrec rad bi se znebu "option" in "drop-down" menija. Namest tega bi blo recimo tko, da se doloci rss source v sami skripti in se potem vsak prikaze in avtomatsko refresh-a v svojem locenem div id-ju.
hvala.

<form>
Select an RSS-feed:
<select onchange="showRSS(this.value)">
<option value="Google">Google News</option>
<option value="MSNBC">MSNBC News</option>
</select>
</form>
<p><div id="rssOutput">
<b>RSS-feed will be listed here...</b></div></p>
</body>

----------------------------------------------

var xmlhttp;
function showRSS(str)
  {
  xmlhttp=GetXmlHttpObject();
  if (xmlhttp==null)
    {
    alert ("Your browser does not support XML HTTP Request");
    return;
    }
  var url="getrss.php";
  url=url+"?q="+str;
  url=url+"&sid="+Math.random();
  xmlhttp.onreadystatechange=stateChanged;
  xmlhttp.open("GET",url,true);
  xmlhttp.send(null);
  }
function stateChanged()
  {
  if (xmlhttp.readyState==4)
    {
    document.getElementById("rssOutput").innerHTML=xmlhttp.responseText;
    }
  }
function GetXmlHttpObject()
{
if (window.XMLHttpRequest)
  {
  // code for IE7+, Firefox, Chrome, Opera, Safari
  return new XMLHttpRequest();
  }
if (window.ActiveXObject)
  {
  // code for IE6, IE5
  return new ActiveXObject("Microsoft.XMLHTTP");
  }
return null;
} 

------------------------------------------

<?php
//get the q parameter from URL
$q=$_GET["q"];
//find out which feed was selected
if($q=="Google")
  {
  $xml=("http://news.google.com/news?ned=us&topic=h&output=rss");
  }
elseif($q=="MSNBC")
  {
  $xml=("http://rss.msnbc.msn.com/id/3032091/device/rss/rss.xml");
  }
$xmlDoc = new DOMDocument();
$xmlDoc->load($xml);

//get elements from "<channel>"
$channel=$xmlDoc->getElementsByTagName('channel')->item(0);
$channel_title = $channel->getElementsByTagName('title')
->item(0)->childNodes->item(0)->nodeValue;
$channel_link = $channel->getElementsByTagName('link')
->item(0)->childNodes->item(0)->nodeValue;
$channel_desc = $channel->getElementsByTagName('description')
->item(0)->childNodes->item(0)->nodeValue;

//output elements from "<channel>"
echo("<p><a href='" . $channel_link
  . "'>" . $channel_title . "</a>");
echo("<br />");
echo($channel_desc . "</p>");
//get and output "<item>" elements
$x=$xmlDoc->getElementsByTagName('item');
for ($i=0; $i<=2; $i++)
  {
  $item_title=$x->item($i)->getElementsByTagName('title')
  ->item(0)->childNodes->item(0)->nodeValue;
  $item_link=$x->item($i)->getElementsByTagName('link')
  ->item(0)->childNodes->item(0)->nodeValue;
  $item_desc=$x->item($i)->getElementsByTagName('description')
  ->item(0)->childNodes->item(0)->nodeValue;

  echo ("<p><a href='" . $item_link
  . "'>" . $item_title . "</a>");
  echo ("<br />");
  echo ($item_desc . "</p>");
  }
?>