var xHRObject = false;

if (window.ActiveXObject)
{
xHRObject = new ActiveXObject("Microsoft.XMLHTTP");
}
else if (window.XMLHttpRequest)
{
xHRObject = new XMLHttpRequest();
}

function getData()
{
    if ((xHRObject.readyState == 4))
    {
    if (xHRObject.status == 200)
    {
         var serverText = xHRObject.responseText;
         if (serverText == "True")
         {
            span.innerHTML = "This user name has already been taken";
         }
         if (serverText == "False")
         {
            span.innerHTML = "This user name is available";
         }
    }
       else
   {
	span.innerHTML = "We cannot currently assess whether this user name is taken or not. It will be checked when you submit the form";
   xHRObject.abort();
   }

    }
}

function getBody(newform, data)
{
     var argument = data + "=";
     argument += encodeURIComponent(document.getElementById(data).value)  
     return argument;
}

function Validate(data)
{
    var newform = document.forms[0];
    var bodyofform = getBody(newform, data); 
    if (bodyofform != "UserName=")
    {
    xHRObject.open("POST", "thisfiledoesntexist.php", true);
    xHRObject.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    xHRObject.onreadystatechange = getData;
    xHRObject.send(bodyofform); ;  
    }
    else
    {
        span.innerHTML = "Blank user names not allowed";
    }
     
}

function Change()
{
    if(state.innerHTML == "State:")
    {
     state.innerHTML = "County:"
     zipcode.innerHTML = "Postcode:"
    }
    else
    {
     state.innerHTML = "State:"
     zipcode.innerHTML = "Zipcode:"
    }
}