Develop Reference

Why do I always get undefined response with this ajax post to php?

I am using mouseover event on span element to initiate an ajax post call to php page, but I always get undefined, first for responseText when I used a simple echo to get response and now when I use responseXML. Can somebody please explain me why.
Here is ajax code:
var span = document.getElementsByTagName('span');
for (var i = 0; i < span.length; i++) {
span[i].addEventListener("mouseover", showInformation, false);
}
function showInformation(event) {
var xhr = new XMLHttpRequest();
xhr.open("POST", "../includes/ajax_response.php", true);
xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhr.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
content(xhr, event);
}
};
xhr.send("uname=" + event.target.firstChild.textContent);
}
function content(xhr, event) {
var info = document.getElementById('displayInformation');
var xmlResponse = xhr.resopnseXML;
var xmlDocumentElement = xmlResponse.documentElement;
var message = xmlDocumentElement.firstChild.data;
info.innerHTML = message;
info.style.visibility = "visible";
event.target.addEventListener("mouseout", function() {
document.getElementById('displayInformation').style.visibility = "hidden";
}, false);
}
And this is php code:
$username = $_POST['uname'];
$query = "SELECT id, joined FROM users WHERE username = '{$username}' LIMIT 1";
$first_result = Database::getInstance()->query($query);
if ($first_result->num_rows == 1) {
foreach ($first_result as $first) {
$id = $first['id'];
$joined = $first['joined'];
}
}
$first_result->free();
$query = "SELECT COUNT(message) AS count FROM blogs WHERE user_id = '{$id}'";
$results = Database::getInstance()->query($query);
if ($results) {
foreach ($results as $result) {
$number = $result['count'];
}
}
header("Content-Type: text/xml");
echo '<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>';
echo '<response>';
echo "joined: {$joined}";
echo "number of posts: {$number}";
echo '</response>';
This is version of php with xml, I tired simpler versions with just
$username = $_POST['uname'] and then echo $username, but always response is
undefined.

I read your code once and there does not seem to be any major error. However, I found out this minor bug:
var xmlResponse = xhr.resopnseXML;
spelling of responseXML is incorrect .. maybe that's what's causing the xmlResponse to be undefined?

Variable is not defined even though it is?

Hi I'm trying to call a php function when a button is pressed but I keep getting the error in the title.
I'm calling the function like so:
echo("<th><input type='button' name = 'Attack_Btn' onclick = 'FightPlayer(".$row['username'].")' value ='Attack'></th>");
just say the username that it gets from $row['user... is James the error will display
index.php:1 Uncaught ReferenceError: casualjames is not defined
This is the code that it calls next
function FightPlayer(enemyName){
var xhttpe;
if (window.XMLHttpRequest) {
xhttpe = new XMLHttpRequest();
} else {
xhttpe = new ActiveXObject("Microsoft.XMLHTTP");
}
xhttpe.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
BattlePlayers();
}
};
xhttpe.open("GET", "FightPlayer.php?enemyname="+enemyName, true);
xhttpe.send();
}
and then it calls my php script passing in the variable enemyname for it to use
<?php
session_start();
include 'Training.php';
$link = mysqli_connect("","","","");
if (isset($_SESSION['username'])) {
$enemyname = $_REQUEST["enemyname"];
echo $enemyname;
$energyRemove = 1;
$ExperienceGain = 1;
$sql = "SELECT * FROM userstats WHERE username = '$enemyname'";
$result = mysqli_query($link,$sql);
$row = mysqli_fetch_assoc($result);
$Defence = $row["Defence"];
$winChance = CalculateWinChance($link,$Defence);
$sql = "SELECT Energy FROM userstats WHERE username = '".$_SESSION['username']."'";
$result = mysqli_query($link,$sql);
$row = mysqli_fetch_assoc($result);
$rand = rand ( 1 , 100 );
if($row["Energy"] < 1 ){
echo "<script type='text/javascript'>alert('Not enough energy to fight. please restore in character page');</script>";
}else{
if($rand < $winChance){
$_SESSION['Battlemessage'] = "you won against ".$enemyname;
$sql = "UPDATE userstats SET `Energy` = `Energy` - '$energyRemove' WHERE username = '".$_SESSION['username']."'";
mysqli_query($link,$sql);
$sql = "UPDATE userstats SET `Experience` = `Experience` + '$ExperienceGain' WHERE username = '".$_SESSION['username']."'";
mysqli_query($link,$sql);
$sql = "UPDATE userstats SET `Satoshi` = `Satoshi` + 2 WHERE username = '".$_SESSION['username']."'";
mysqli_query($link,$sql);
}else{
$_SESSION['Battlemessage'] = "you lost against ".$enemyname;
$sql = "UPDATE userstats SET `Energy` = `Energy` - '$energyRemove' WHERE username = '".$_SESSION['username']."'";
mysqli_query($link,$sql);
$sql = "UPDATE userstats SET `Satoshi` = `Satoshi` + 1 WHERE username = '".$enemyname."'";
mysqli_query($link,$sql);
}
echo "";
}
calculateLevel($link);
}
?>
I'm not sure where the error is actually happening I've put my scripts through online code checkers and it all returns normal. Where am I going wrong here?

The string you're passing into your javascript function needs to be quoted, or else it thinks that it's a variable:
echo("<th><input type='button' name = 'Attack_Btn' onclick = 'FightPlayer(\"".$row['username']."\")' value ='Attack'></th>");

Your error is most likely with the onclick...you need to escape quotes in the function argument here:
echo("<th><input type='button' name = 'Attack_Btn' onclick = 'FightPlayer(\"".$row['username']."\")' value ='Attack'></th>");

Why am I not able to fetch property of the object that I get from PHP?

I am trying to receive data from database based on the name entered by user, everything works fine I do see the value on screen and no error Here is the php code :
<?php
$dbhost = "localhost";
$username = "root";
$password = "";
mysql_connect($dbhost,$username,$password);
#mysql_select_db("trynew") or die(mysql_error());
$user ="mon";
$query = "SELECT * FROM trynewtable where name = '$user' ";
$all_result = array();
$result = mysql_query($query);
if($result==FALSE)
{
die(mysql_error());
}
while($row = mysql_fetch_assoc($result))
{
$all_result[] = $row;
}
header('Content-Type: application/json');
$jsondata = json_encode($all_result);echo $jsondata;
mysql_close();
?>
JavaScript code :
var loadingFunc=function()
{
var xhr;
if(window.XMLHttpRequest)
{
xhr = new XMLHttpRequest();
}
else
{
xhr = new ActiveXObject('Microsoft.XMLHTTP');
}
var jsonData= "";
xhr.onreadystatechange =function()
{
if(xhr.readyState==4)
{
if(xhr.success =200)
{
jsonData = xhr.responseText;
document.getElementById("dvID").innerHTML = jsonData;
//var parsejson = JSON.parse(jsonData);
//document.getElementById("dvIDO").innerHTML = parsejson.age;
document.getElementById("dvIDO").innerHTML = jsonData[0].age;
}
else
{
document.getElementIdById("dvID").innerHTML = "it's not success ";
}
}
else
{
console.log("error is here");
console.log(xhr.readyState);
}
}
var element1 = document.getElementById("dvID") ;
xhr.open("POST","index.php");
xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
var sendD = document.getElementById("data_found").value;
var data = "data_found=" + sendD;
var element = document.getElementById("btn") ;
if(element)
{
element.addEventListener('click',function(){
console.log("just clicked")
xhr.send(data);
})
}
};
window.onload = loadingFunc();
but the output that I see on the html div is :
[{"id":"1","Name":"mon","Age":"26","Gender":"F"}]
undefined
I am getting the whole object but whenever I am trying to fetch any property of the object like age here (parsejson.age or jsonData[0].age) it's showing undefined , Could anyone help me how do I fetch any property of the object?
Kindly let me know what am I doing wrong ?

First transform the cleartext response into a javascript object. You have the line already there but commented out it seems, after that:
alert(jsonData["Age"]); //Age
alert(jsonData.Age); //Age

php returns empty JSON array

I created an array for town name, "Auckland" and "Hamilton", but the response from php is always empty, any idea?
UPDATE:
after debugging, I found that the problem is in php query
" where town = '$town' ", once i deleted this line, the rest works perfectly.
But I still can't figure out why :<
javascript:
var _addNewTowntoList = function(){
if (_request.readyState == 4) {
if (_request.status == 200) {
var data = JSON.parse(_request.responseText);
if(data.length == 0){
alert("No such town");
return;
}
var t = data[0].town;
var o = data[0].outlook;
var min = data[0].min_temp;
var max = data[0].max_temp;
var witem = new WLine(t,o,min,max);
console.log(t+" "+o+" "+min+" "+max);
_list.push(witem);
}
}
}
here is the php
$town = $POST_['town'];
$query = "Select * From weather WHERE town = '$town'";
$result = mysqli_query($conn, $query);
//create array for data
$data = array();
while($row = mysqli_fetch_assoc($result))
{
$data[] = $row;
}
echo json_encode($data);

change this
$town = $POST_['town'];
> $query = "Select * From weather WHERE town = '$town'";
to
$town = $_POST['town'];
$query = "Select * From weather WHERE town = '".$town."'";

Remember to properly escape the query string
$town = mysqli_real_escape_strin($conn, $_POST['town']);
Because else your script is opened to SQL Injection attack
The other thing to mention here other than correct name for the $_POST is that you can use mysqli_fetch_all function to fetch all results at once and avoid the loop. For example
echo json_encode(mysqli_fetch_all($result, MYSQLI_ASSOC));

Turning PHP into JSON array when parsed in Javascript

So, in order to create a page that has dynamic HTML, the following Javscript code was used:
function add0(Text, Value){
var x = document.getElementById("thingy");
var option = document.createElement("option");
option.text = Text;
option.value = Value;
x.add(option);}
function add(Text, Value){
var x = document.getElementById("stuff");
var option = document.createElement("option");
option.text = Text;
option.value = Value;
x.add(option);}
var c = 0;
var value =<?php echo json_encode($ToAndFromR); ?>;
var formula = <?php echo json_encode($FormulaR); ?>;
while(c < <?php echo $countr ?>){
add0(value[c], formula[c]);
add(value[c], formula[c]);
c++;
}
This was done after recieving $ToAndFromR and $Formula from a SQL Query, in which the code is :
$conn = mysqli_connect($servername, $username, $password, $dbname);
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
//declare variables
$countr = null;
$sql = "SELECT * FROM `convert`";
$drippage = mysqli_query($conn, $sql);
//this counts the number of rows
if (mysqli_num_rows($drippage)) {
$countr = mysqli_num_rows($drippage);
}
$ToAndFrom = mysqli_query($conn, "SELECT ToAndFrom FROM `convert`");
$ToAndFromR = null;
$ToAndFromR = mysqli_fetch_all($ToAndFrom, MYSQLI_BOTH);
$FormulaR = null;
$Formula = mysqli_query($conn, "SELECT Formula FROM `convert`");
$FormulaR = mysqli_fetch_all($Formula, MYSQLI_BOTH);
However, the HTML gets shown as [object Object] in the dropdown list, as opposed to their actual values when a regular PHP array is used. Is there a way to fix this?

Each Text and Value passed to your JavaScript functions will be an object with two properties (because you're using MYSQLI_BOTH fetch mode), eg
{"0": "some value", "ToAndFrom": "some value"}
You're attempting to assign this to the option's text and value properties.
You also appear to be running three queries when you should be running one.
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$conn = new mysqli($servername, $username, $password, $dbname);
$conn->set_charset('utf8');
$result = $conn->query('SELECT `ToAndFrom` AS `text`, `Formula` AS `value` FROM `convert`');
$options = $result->fetch_all(MYSQLI_ASSOC);
and in your JavaScript
var options = <?= json_encode($options) ?>;
for (var i = 0, l = options.length; i < l; i++) {
add0(options[i].text, options[i].value);
add(options[i].text, options[i].value);
}
Also, you could cut down on the almost identical JavaScript functions add0 and add by simply passing the <select> ID, eg
function add(selectId, text, value) {
var x = document.getElementById(selectId);
// and so on
}
with
add('thingy', options[i].text, options[i].value);
add('stuff', options[i].text, options[i].value);

I think you should write a separate PHP script which echo the JSON.
Then in the javascript, you should call this PHP and parse the JSON. A simple code:
var xhr = new XMLHttpRequest();
xhr.open("GET", "sql.php", true);
var htmltext= '';
xhr.onload = function (e) {
if (xhr.readyState === 4) {
if (xhr.status === 200) {
var jsoninfo = xhr.responseText;
var obj = JSON.parse(jsoninfo);
// text = obj.attribute;
// add0(text,formula[c])
}
}
}