I have one simple html form where the fields can be auto populated by entering ID. its working fine. but, if ID not found in database, it can only return null to the form fields. i was trying to display an error message (can be a pop-up window) saying **ID not found!** but i failed to do it. here is my code to echo info into the form field:

```
if (strlen($param) > 0) {
    $result = mysql_query("SELECT * FROM contact 
     WHERE contactid LIKE '$param%'");
    if (mysql_num_rows($result) == 1) {
        while ($myrow = mysql_fetch_array($result)) {
            $agentname = $myrow["contactfullname"];
            $agenttel = $myrow["contacttel"];
            $agentsal = $myrow["contactsalutation"];
            $agentid = $myrow["contactid"];
            $textout .= $agentid . ", " . $agentname . ", " . $agenttel . ", " . $agentsal;
        }
    } else {
        $textout = " , , ," . $param;
    }
}
echo $textout;

```

here is my ajaxFunction:

```
function ajaxFunction(e){
    var e=e || window.event;
    var keycode=e.which || e.keyCode;
    if(keycode==13 || (e.target||e.srcElement).value==''){ 
    var http;  // The variable that makes Ajax possible! 

    try{ 
        // Opera 8.0+, Firefox, Safari 
        http = new XMLHttpRequest(); 
    } catch (e){ 
        // Internet Explorer Browsers 
        try{ 
            http = new ActiveXObject("Msxml2.XMLHTTP"); 
        } catch (e) { 
            try{ 
                http = new ActiveXObject("Microsoft.XMLHTTP"); 
            } catch (e){ 
                // Something went wrong 
                alert("Your browser broke!"); 
                return false; 
            } 
        }
    }
 var url = "getagentids.php?param=";
                var idValue = document.getElementById("agid").value;
                var myRandom = parseInt(Math.random()*99999999);  // cache buster
                http.open("GET", "getagentids.php?param=" + escape(idValue) + "&rand=" + myRandom, true);
                http.onreadystatechange = handleHttpResponse;
                http.send(null);

                function handleHttpResponse() {
                    if (http.readyState == 4) {
                        results = http.responseText.split(",");
                        document.getElementById('agfn').value = results[0];
                        document.getElementById('agsal').value = results[1];
                        document.getElementById('agtel').value = results[2];
                        document.getElementById('agid').value = results[3];
                    }
           } 
    }   
}

```