can't make cross browser AJAX request to work - php

I am doing a simple ajax request to another domain like this:
<script type="text/javascript">
$(function() {
$('.clik').click(function() {
$.ajax({
type: "POST",
url: "http://sub.mydomain.com/test.php",
crossDomain: true,
dataType:"jsonp",
success: function(data) {
$('p.txt').html(data['no']);
}
});
});
});
</script>
</head>
<body>
<p class="clik">Halleluja</p>
<p class="txt"></p>
this is the test.php page on sub.mydomain.com
<?
header('Access-Control-Allow-Origin: http://mydomain.com');
// Begin Session
require_once('cl.session.php');
$session = new Session();
$session->start_session('test', false);
// Access Database
require_once('cl.database.php');
$login_db = new Database('user', 'pass', 'accounts', 'test');
$login_pdo = $login_db->PDO;
include "fn.check_login.php";
if(checkLogin($login_pdo) == true) {
// We start out by checking if the request has been made using AJAX
if (is_ajax()) {
echo "this is working";
} else {
echo "this is not working!";
}
} else {
echo 'You are not authorized to access this page, please login. <br/>';
}
// Function to check if the request is an AJAX request
function is_ajax() {
// BOOLEAN return if AJAX
return isset($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest';
}
?>
It returns a semantic issue.
Also if I simply echo some basic text:
<?
echo "Hello World!";
?>
it still returns a semantic issue.
could somebody tell me what went wrong?

Well, for a start, JSONP requests can't be POST (only GET). But I tend to assume jQuery is ignoring the invalid type. JSONP is intrinsically a GET.
Your response to it is invalid. You've told jQuery you're expecting the server to provide a JSONP response. but your responses aren't JSONP.
A JSONP response would look something like this:
callback({
"property": "value",
"anotherProperty": 42
})
...where the name of the callback (callback in the above) is taken from the query string of the request. So for instance, if the request were http://sub.mydomain.com/test.php?callback=foo, the response would use foo for the name of the callback:
foo({
"property": "value",
"anotherProperty": 42
})
jQuery will add the callback= query string parameter to the request for you automatically, and generate the corresponding function for you, which in turn calls the ajax success handler with the data passed into it.

I think you may need to use the jquery postMessage plugin (or similar if there is one). Long time since I tried it but check if you load the script from the server you wish to call (think I tried that and failed in the past but hey - its worth a bash - report back if it does).

Related

Running a PHP Script without redirecting or refreshing the page

I am very new to PHP and Javascript.
Now I am running a PHP Script by using but it redirect to another page.
the code is
<a name='update_status' target='_top'
href='updateRCstatus.php?rxdtime=".$time."&txid=".$txid."&balance=".$balance."&ref=".$ref."'>Update</a>
How do I execute this code without redirecting to another page and get a popup of success and fail alert message.
My script code is -
<?PHP
$rxdtime=$_GET["rxdtime"];
$txid=$_GET["txid"];
$balance=$_GET["balance"];
$ref=$_GET["ref"];
-------- SQL Query --------
?>
Thanks in advance.
You will need to use AJAX to do this. Here is a simple example:
HTML
Just a simple link, like you have in the question. However I'm going to modify the structure a bit to keep it a bit cleaner:
<a id='update_status' href='updateRCstatus.php' data-rxdtime='$time' data-txid='$txid' data-balance='$balance' data-ref='$ref'>Update</a>
I'm assuming here that this code is a double-quoted string with interpolated variables.
JavaScript
Since you tagged jQuery... I'll use jQuery :)
The browser will listen for a click event on the link and perform an AJAX request to the appropriate URL. When the server sends back data, the success function will be triggered. Read more about .ajax() in the jQuery documentation.
As you can see, I'm using .data() to get the GET parameters.
$(document).ready(function() {
$('#update_status').click(function(e) {
e.preventDefault(); // prevents the default behaviour of following the link
$.ajax({
type: 'GET',
url: $(this).attr('href'),
data: {
rxdtime: $(this).data('rxdtime'),
txid: $(this).data('txid'),
balance: $(this).data('balance'),
ref: $(this).data('ref')
},
dataType: 'text',
success: function(data) {
// do whatever here
if(data === 'success') {
alert('Updated succeeded');
} else {
alert(data); // perhaps an error message?
}
}
});
});
});
PHP
Looks like you know what you're doing here. The important thing is to output the appropriate data type.
<?php
$rxdtime=$_GET["rxdtime"];
$txid=$_GET["txid"];
$balance=$_GET["balance"];
$ref=$_GET["ref"];
header('Content-Type: text/plain; charset=utf-8');
// -------- SQL Query -------
// your logic here will vary
try {
// ...
echo 'success';
} catch(PDOException $e) {
echo $e->getMessage();
}
Instead of <a href>, use ajax to pass the values to your php and get the result back-
$.post('updateRCstatus/test.html', { 'rxdtime': <?php ecdho $time ?>, OTHER_PARAMS },
function(data) {
alert(data);
});

PHP interaction with AJAX

So I have this function in my javascript file:
function UpdateThisCourseHistory(){
var ajax= new Ajax.Request("runNeededQueries.php",
{
method: "POST",
parameters: {database: "history", action:"update"},
onSuccess: function(){alert("This Course History Entry Has Been Updated");},
onFailure: function(){alert("Could Not Find The Entry With The Specified Primary Key");}
}
);
}
Suppose this is my php file
<?php
header('HTTP/1.0 400 Bad Request');
?>
Would this make the onFailure method execute?
The onSuccess callback will fire when the PHP script responds with an HTTP 2xx response code and the onFailure callback will fire if an HTTP error code is returned. If you want to take action based on the response value, you have to options:
Modify your PHP script to return an HTTP error response (perhaps 400) on failure and take action based on the specific value returned.
header('HTTP/1.0 400 Bad Request');
Update your AJAX handler to inspect the data that is returned and take action based on its content.
onSuccess: function(transport){ if transport.responseText == 'expected value' ...}
Make your PHP script output something, preferably in JSON.
Like:
{ action: 'find_id', status: true }
Get the data from response, so you can see if an action was successful or not.
function(data){
if (data.status){
alert("Everything is OK") ;
} else {
alert("Failed") ;
}
}

$.post json request doesn't return any result

Well, another try:
this is all the jquery code i'm using maybe i made something wrong in the code before $.post(); i call the following function with the onclick of the same form...
function setLogin()
{
$('#login-form').submit(function(e) {
e.preventDefault();
//passing form field to vars
var formUsername=$("#login-form #username").val();
var formPassword=$("#login-form #password").val();
//checks on fields lenght
if((formUsername.length<6))
{
$("#ajax-output").html("<div class='error'>Attenzione username troppo breve!</div>");
}
else if((formPassword.length<6))
{
$("#ajax-output").html("<div class='error'>Attenzione password troppo breve!</div>");
}
else
{
$.post(
//the url
'?module=login',
//data got from login form
{
"username": formUsername,
"password": formPassword,
},
//response
function(data){
$("#ajax-output").html(data.reply)
},
//type
"json"
);
}
});
}
i tried with only this code in php file and it still doesn't return anything...
function Login()
{
//just to try
echo json_encode(array('reply'=>'foo'));
}
it still doesn't work...
Are you sure the post is being run in the first place?
Use Firebug! (or chrome's built-in developer tools)
You can use firebug to pick apart every bit of a web page.
It has a "net" tab that shows every request that is made by the browser, including AJAX requests, and their results, headers and contents.
Use it to see if your requests is really being made, and what the result is. Then take it from there.
Make sure that you're setting a header for the content type when responding - the browser may not attempt to use the JSON if it doesn't know it's receiving JSON.
function Login()
{
header('Content-Type: application/json');
echo json_encode(array('reply'=>'foo'));
}

How can I "read" a response from the php file I call here using ajax?

I am very new to ajax and jquery, but I came across a code on the web which I am manipulating to suit my needs.
The only problem is that I want to be able to respond to the ajax from PHP.
This ajax POSTS to a php page (email.php).
How can I make the email.php reply back if the message is sent or if message-limit is exceeded (I limit the nr of messages sent per each user)?
In other words, I want ajax to take a 1 or 0 from the php code, and for example:
if(response==1){ alert("message sent"); } else { alert("Limit exceeded"); }
Here is the last part of the code: (If you need the full code just let me know)
var data_string = $('form#ajax_form').serialize();
$.ajax({
type: "POST",
url: "email.php",
data: data_string,
success: function() {
$('form#ajax_form').slideUp('slow').before('');
$('#success').html('<h3>Success</h3>Your email is has been sent.');
}//end success function
}) //end ajax call
return false;
})
Thanks
The success function of an $.ajax call receives a parameter, usually called data though that's up to you, containing the response, so:
success: function(data) {
// Use the data
}
(It also receives a couple of other parameters if you want them; more in the docs.)
The data parameter's type will vary depending on the content type of the response your PHP page sends. If it sends HTML, data will be a string containing the HTML markup; if your page sends JSON, the data parameter will be the decoded JSON object; if it's XML, data will be an XML document instance.
You can use 1 or 0 if you like (if you do, I'd probably set the content type to "text/plain"), so:
success: function(data) {
if (data === "1") {
// success
}
else if (data === "0") {
// failure
}
else {
// App error, expected "0" or "1"
}
}
...but when I'm responding to Ajax requests, nine times out of ten I send JSON back (so I set the Content-Type header to application/json), because then if I'm using a library like jQuery that understands JSON, I'll get back a nice orderly object that's easy to work with. I'm not a PHP guy, but I believe you'd set the content type via setContentType and use json_encode to encode the data to send back.
In your case, I'd probably reply with:
{"success": "true"}
or
{"success": "false", "errMessage": "You reached the limit."}
so that the server-side code can dictate what error message I show the user. Then your success function would look like this:
success: function(data) {
var msg;
if (typeof data !== "object") {
// Strange, we should have gotten back an object
msg = "Application error";
}
else if (!data.success) {
// `success` is false or missing, grab the error message
// or a fallback if it's missing
msg = data.errMessage || "Request failed, no error given";
}
if (msg) {
// Show the message -- you can use `alert` or whatever
}
}
You must pass an argument to your "success" function.
success: function(data)
{
if(data == '1')
{
$('form#ajax_form').slideUp('slow').before('');
$('#success').html('<h3>Success</h3>Your email is has been sent.');
}
}
And in your php file, you should just echo the response you need
if(mail())
{
echo '1';
}
else
{
echo '0';
}
Anything you echo or return in the php file will be sent back to you jquery post. You should check out this page http://api.jquery.com/jQuery.post/ and think about using JSON formatted variables to return so like if you had this in your email script:
echo '{ "reposonse": "1" }';
This pass a variable called response with a value of 1 back to you jquery script. You could then use an if statement how you described.
just have email.php echo a 0 or 1, and then grab the data in the success event of the ajax object as follows...
$.ajax({
url: 'email.php',
success: function(data) {
if (data=="1"){
...
}else{
...
}
}
});
what you do is, you let your ajax file (email.php) print a 1 if successful and a 0 if not (or whatever else you want)
Then, in your success function, you do something like this:
function(data) {
$('form#ajax_form').slideUp('slow').before('');
if(data==1){ alert("message sent"); } else { alert("Limit exceeded"); }
$('#success').html('<h3>Success</h3>Your email is has been sent.');
}
So you capture the response in the data var of the function. If you a bigger variety in your output, you can set you dataType to "json" and have your php file print a json_encoded string so that you can access your different variables in your response via for example data.success etc.
PHP can only return to AJAX calls, by its output. An AJAX call to a PHP page is essentially the same as a browser requesting for the page.
If your PHP file was something like,
<?php
echo "1";
?>
You would receive the "1" in your JavaScript success callback,
that is,
success: function(data) {
// here data is "1"
}
As an added note, usually AJAX responses are usually done in JSON format. Therefore, you should format your PHP replies in JSON notation.

Getting json on Ajax response callback

I am trying to create a little ajax chat system (just for the heck of it) and I am using prototype.js to handle the ajax part.
One thing I have read in the help is that if you return json data, the callback function will fill that json data in the second parameter.
So in my php file that gets called I have:
header('Content-type: application/json');
if (($response = $acs_ajch_sql->postmsg($acs_ajch_msg,$acs_ajch_username,$acs_ajch_channel,$acs_ajch_ts_client)) === true)
echo json_encode(array('lastid' => $acs_ajch_sql->msgid));
else
echo json_encode(array('error' => $response));
On the ajax request I have:
onSuccess: function (response,json) {
alert(response.responseText);
alert(json);
}
The alert of the response.responseText gives me {"lastid": 8 } but the json gives me null.
Anyone know how I can make this work?
This is the correct syntax for retrieving JSON with Prototype
onSuccess: function(response){
var json = response.responseText.evalJSON();
}
There is a property of Response: Response.responseJSON which is filled with a JSON objects only if the backend returns Content-Type: application/json, i.e. if you do something like this in your backend code:
$this->output->set_content_type('application/json');
$this->output->set_output(json_encode($answer));
//this is within a Codeigniter controller
in this case Response.responseJSON != undefined which you can check on the receiving end, in your onSuccess(t) handler:
onSuccess:function(t) {
if (t.responseJSON != undefined)
{
// backend sent some JSON content (maybe with error messages?)
}
else
{
// backend sent some text/html, let's say content for my target DIV
}
}
I am not really answering the question about the second parameter of the handler, but if it does exist, for sure Prototype will only provide it in case of proper content type of the response.
This comes from Prototype official :
Evaluating a JavaScript response
Sometimes the application is designed
to send JavaScript code as a response.
If the content type of the response
matches the MIME type of JavaScript
then this is true and Prototype will
automatically eval() returned code.
You don't need to handle the response
explicitly if you don't need to.
Alternatively, if the response holds a
X-JSON header, its content will be
parsed, saved as an object and sent to
the callbacks as the second argument:
new Ajax.Request('/some_url', {
method:'get', onSuccess:
function(transport, json){
alert(json ? Object.inspect(json) : "no JSON object");
}
});
Use this functionality when you want to fetch non-trivial
data with Ajax but want to avoid the
overhead of parsing XML responses.
JSON is much faster (and lighter) than
XML.
You could also just skip the framework. Here's a cross-browser compatible way to do ajax, used in a comments widget:
//fetches comments from the server
CommentWidget.prototype.getComments = function() {
var commentURL = this.getCommentsURL + this.obj.type + '/' + this.obj.id;
this.asyncRequest('GET', commentURL, null);
}
//initiates an XHR request
CommentWidget.prototype.asyncRequest = function(method, uri, form) {
var o = createXhrObject()
if(!o) { return null; }
o.open(method, uri, true);
o.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
var self = this;
o.onreadystatechange = function () {self.callback(o)};
if (form) {
o.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
o.send(makePostData(form));
} else {
o.send('');
}
}
//after a comment is posted, this rewrites the comments on the page
CommentWidget.prototype.callback = function(o) {
if (o.readyState != 4) { return }
//turns the JSON string into a JavaScript object.
var response_obj = eval('(' + o.responseText + ')');
this.comments = response_obj.comments;
this.refresh()
}
I open-sourced this code here http://www.trailbehind.com/comment_widget

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