var xmlHttp

function loginv(str){ 
xmlHttp=GetXmlHttpObject()
if (xmlHttp==null)
 {
 alert ("Browser does not support HTTP Request")
 return
 }
var url="login.php"

if(str == "login")
url=url+"?userid="+document.getElementById('userid').value+"&password="+document.getElementById('password').value

if(str == "logout")
url=url+"?logout=logout"

xmlHttp.onreadystatechange=stateChanged 
xmlHttp.open("GET",url,true)
xmlHttp.send(null) 
}

function stateChanged() 
{ 
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
 { 
 document.getElementById("loginpanel").innerHTML=xmlHttp.responseText 
 } 
}

function GetXmlHttpObject()
{
var xmlHttp=null;
try
 {
 // Firefox, Opera 8.0+, Safari
 xmlHttp=new XMLHttpRequest();
 }
catch (e)
 {
 //Internet Explorer
 try
  {
  xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
  }
 catch (e)
  {
  xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
 }
return xmlHttp;
}