Need help with a chat room script

[fert]

I've just started Ajax and this is some code I came up with for a chat room
Here's my code
[code]
function makerequest()
{
var request;
if (window.XMLHttpRequest)
{
        request = new XMLHttpRequest();
}
else
if (window.ActiveXObject)  // ActiveX version
{
      request = new ActiveXObject("Microsoft.XMLHTTP");
}

request.onreadystatechange = function()
if(request.readyState == 4)
  {
      if(request.status == 200)
          document.chat.text.value="Received:" + req.responseText;
      else
          document.chat.text.value="Error code " + req.status;
  }
  req.open(POST,"chat.php",true);
  req.send("?text="+encode(document.chat.new_text.value)+"&user="+encode(document.chat.username.value));
}

function update()
{
var request;
if (window.XMLHttpRequest)
{
        request = new XMLHttpRequest();
}
else
if (window.ActiveXObject)  // ActiveX version
{
      request = new ActiveXObject("Microsoft.XMLHTTP");
}

request.onreadystatechange = function()
if(request.readyState == 4)
  {
      if(request.status == 200)
          document.chat.text.value=" + req.responseText;
      else
          document.chat.text.value="Error code " + req.status;
  }
  req.open(GET,"chat.php",true);
  req.send(null);
}
[/code]
The code isn't updating the database (which is what chat.php does). can anybody tell me why?

[hvle]

when you POST from ajax to a php script, your SEND content do not got populated into $_POST.  check this out to make sure.
Instead, it ended up in $_GLOBALS['HTTP_RAW_POST_DATA']
something like that, I'm not so sure about the name, but you should do some echo and check.

[fert]

thanks now it works