Trying to retrieve Session Variable

[XpertWorlock]

Hi, I'm making a simple js function that retrieves Session variables.  It works when you assign the response to an ID, I just want to have it return.

 

function getSessionVariable(id)
{

var xmlHttp=GetXmlHttpObject();
if (xmlHttp==null)
  {
  alert ("Your browser does not support AJAX!");
  return;
  } 
var url="getSessionVariable.php";
var params = 'id='+id+'&sid='+Math.random();
xmlHttp.open("POST",url,true);
xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlHttp.setRequestHeader("Content-length", params.length);
xmlHttp.setRequestHeader("Connection", "close");

xmlHttp.onreadystatechange=function()
{

if (xmlHttp.readyState==4)
{ 
return xmlHttp.responseText

}

}

xmlHttp.send(params);



} 

 

I don't need to show you the PHP page it requests, because like I said, it works perfectly if assigning the response to an ID.

 

But if I write something like this in js

 

alert(getSessionVariable('userName'))

 

it pops up undefined, making me understand that the problem is "return xmlHttp.responseText"

 

 

 

[rhodesa]

AJAX is asynchronous. this means that the getSessionVariable() will finish before the HttpRequest is complete. what this means is that you can't return from the onreadystatechange() function. instead, put what you want to do inside the if or use this, and put what you want it to do inside the onComplete() function:

<script>
function getSessionVariable(id)
{
  var xmlHttp=GetXmlHttpObject();
  if (xmlHttp==null)
  {
    alert ("Your browser does not support AJAX!");
    return;
  }
  var url="getSessionVariable.php";
  var params = 'id='+id+'&sid='+Math.random();
  xmlHttp.open("POST",url,true);
  xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
  xmlHttp.setRequestHeader("Content-length", params.length);
  xmlHttp.setRequestHeader("Connection", "close");
  
  xmlHttp.onreadystatechange=function()
  {
    if (xmlHttp.readyState==4)
    {
      onComplete(xmlHttp.responseText);
      return;
    }
  }

  xmlHttp.send(params);
}
function onComplete ( response ) {
  alert(response);
}
</script>

[rhodesa]

p.s. - you don't need to add the random number, as POSTs are not cached. also, you can shorten this code up by using jquery:

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js"></script>
<script type="text/javascript">
function (id){
  $.post("getSessionVariable.php", { 'id': id }, function ( data ){
    alert(data);
  });
}
</script>

[XpertWorlock]

Thanks for the POST cache info, didn't think of that.  I see what you mean that getSessionVariable() ends before the HttpRequest, is there anyway of getting it like this than:

 

If $_SESSION['userName'] = "Jeff";

 

 

if I write in JS

 

var userName = getSessionVariable('userName');
document.write(userName);

I want it to write Jeff, or alert, etc.  Trying to make it open ended for whatever I need it to do.

 

Is this possible?

 

 

 

 

 

[rhodesa]

no...the function that starts the AJAX can't return the value. you MIGHT be able to turn async off, but not sure.