var req;
var feldname;
var form_id;
function pruefe_eingabe(eingabe, feldname, form_id)
{
    if (window.ActiveXObject)
    {
       try
       {
            req = new ActiveXObject("Msxml2.XMLHTTP");
       } catch (e)
       {
            try
            {
                req = new ActiveXObject("Microsoft.XMLHTTP");

            } catch (e)
            {
            }
       }
    } else if (window.XMLHttpRequest)
    {
        try
        {
            req = new XMLHttpRequest();
        } catch (e)
        {
        }
    }
    if (req)
    {
        callurl = 'fileadmin/scripts/checkdata.php?text='+ eingabe+'&feld='+feldname+'&form_id='+form_id;
        req.open("GET", callurl, true);
        req.onreadystatechange = processReqChange;
        req.send(null);
    }
}

function processReqChange()
{
    if (req.readyState == 4)
    {
        if (req.status == 200)
        {
        }
    }
}