Question

I am not getting response while fetching result from my code using AJAX. while sending parameters to file my code is working good… that is, sending parameters to file , as I have checked using alert msg..
but my php file is not showing any response.

AJAX CODE.

function viewsg(){

document.getElementById('sgwaitingmsg').innerHTML = "Just a second...";
var childid = encodeURIComponent(document.getElementById('childsgselect').value);
var parameters ='childid=' + childid;
http.open('POST', 'fetchsg.php', true);
http.send(parameters);
//alert(parameters);
http.onreadystatechange = function(){
      if (xmlhttp.readyState==4 && xmlhttp.status==200 )
    {
    document.getElementById("sgwaitingmsg").innerHTML=xmlhttp.responseText;
        }
    }
}

PHP CODE.

<?php
//$_REQUEST["childid"];
//$_REQUEST["nocache"];
echo $_REQUEST["childid"];
?>

HTML CODE.

<label id="sgwaitingmsg"></label>
<select id="childsgselect" onchange="viewsg()" >
<option value="">Select Child</option>
<?php while($result=mysql_fetch_assoc($child)){print '<option value="'.$result["snum"].'">'.$result["sfname"].'</option>'; }?>
</select>

Answer 1

$_REQUEST["childid"]; does not do anything. try

echo $_POST["childid"]; 

instead

and you have syntax error in your code

if (xmlhttp.readyState==4 && )

should be

if (xmlhttp.readyState==4)

Try this one http://sandbox.phpcode.eu/g/904ed/10

<?php 
if (isset($_POST['childid'])){ 
    echo $_POST['childid']; 
    die(); 
}  
?> 
<div id="sgwaitingmsg"></div> 
<input id="childsgselect" value="hellllo" /> 
<script> 
function viewsg(){ 

document.getElementById('sgwaitingmsg').innerHTML = "Just a second..."; 
var childid = encodeURIComponent(document.getElementById('childsgselect').value); 
var parameters ='childid=' + childid; 
var params ='childid=' + childid; 
http=new XMLHttpRequest(); 
http.open('POST', '<?php echo $_SERVER['PHP_SELF']; ?>', true); 
http.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); 
http.setRequestHeader("Content-length", params.length); 
http.setRequestHeader("Connection", "close"); 
http.send(parameters); 
//alert(parameters); 
http.onreadystatechange = function(){ 
      if (http.readyState==4) 
    { 
    document.getElementById("sgwaitingmsg").innerHTML=http.responseText; 
        } 
    } 
} 
viewsg(); 
</script>

is fully working script. You’ll have to go through