I have created a simple ajax request:
var params = "postdata=" + mydata;
if (window.XMLHttpRequest) {
xmlhttp = new XMLHttpRequest();
} else {
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange = function () {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
document.getElementById("data").innerHTML = xmlhttp.responseText;
}
}
xmlhttp.open("POST", "data.php", true);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.setRequestHeader("Content-length", params.length);
xmlhttp.setRequestHeader("Connection", "close");
xmlhttp.send(params);
And this is the HTML code:
<div id="data">
<img src="/images/preload.gif" />
<b style="color:#9ca6dc;font-size:12px;">Wait</b>
</div>
The problem is that the preload.gif and "Wait" text appears only sometimes and not always.
Why ? How can I resolve that ?
The only explanation is that AJAX request works too quickly to see the content (as Alessandro Pezzato said). If you don't see it the readyState of XMLHTTP request had to change.
Or you have some other Javascript which runs asynchronously and does changes on the same content.
Related
I am using Flask with Python. From the Flask method I am trying to return HTML table rows in an AJAX call.
The HTML page has:
<div>
<table id="tableQuestions">
</table>
//AJAX Requests to get
function loadQuestions() {
var xmlHttp = new XMLHttpRequest();
xmlHttp.onreadystatechange = function() {
alert(xmlHttp.readyState + " " + xmlHttp.status);
if (xmlHttp.readyState==4 && xmlHttp.status == 200) {
var response = xmlHttp.responseText;
console.log(response);
document.querySelector("#tableQuestions").innerHTML=response;
}
xmlHttp.open("GET", '/gS', true);
xmlHttp.send(null);
}
}
The Flask route has:
#test.mix() returns html table rows
#gbp.route('/gS')
def gS():
test=mn()
response = make_response(test.mix(quesCount=4),200)
response.mimetype="text/html"
In the Safari debugger I can see that the responseText has the table data from the server, but readystate remains 1 and status = 0.
Could you please suggest how I can overcome this issue?
You have
xmlHttp.open("GET", '/gS', true);
xmlHttp.send(null);
inside your xmlHttp.onreadystatechange callback function, which leads to strange effects.
The following code (untested) should behave better:
//AJAX Requests to get
function loadQuestions() {
var xmlHttp = new XMLHttpRequest();
xmlHttp.open("GET", '/gS', true);
xmlHttp.onreadystatechange = function() {
alert(xmlHttp.readyState + " " + xmlHttp.status);
if (xmlHttp.readyState==4 && xmlHttp.status == 200) {
var response = xmlHttp.responseText;
console.log(response);
document.querySelector("#tableQuestions").innerHTML=response;
}
}
xmlHttp.send(null);
}
This question already has answers here:
Send POST data using XMLHttpRequest
(13 answers)
Closed 8 years ago.
I'm sending a string via xmlhttp in javascript using the following code:
function SendPHP(str, callback) {
if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp = new XMLHttpRequest();
} else { // code for IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange = function () {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
callback(xmlhttp.responseText); //invoke the callback
}
}
xmlhttp.open("GET", "testpost.php?q=" + encodeURIComponent(str), true);
xmlhttp.send();
}
and some test php:
$q = $_GET['q'];
echo $q;
That worked fine until I started sending a larger string in which case I get the "HTTP/1.1 414 Request-URI Too Long" error.
After a bit of research I found out I need to use "POST" instead. So I changed it to:
xmlhttp.open("POST", "sendmail.php?q=" + str, true);
And:
$q = $_POST['q'];
echo $q;
But this does not echo anything when using POST. How can I fix it so it works like when I was using GET but so it can handle a large string of data?
edit I'm now trying it with:
function testNewPHP(str){
xmlhttp = new XMLHttpRequest();
str = "q=" + encodeURIComponent(str);
alert (str);
xmlhttp.open("POST","testpost.php", true);
xmlhttp.onreadystatechange=function(){
if (xmlhttp.readyState == 4){
if(xmlhttp.status == 200){
alert (xmlhttp.responseText);
}
}
};
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send(str);
}
You should not provide your href with URL parameters, instead of this you should send() them. For addition, you should always encode your parameters with encodeURIComponent() (At least when your request is using the Content-type "application/x-www-form-urlencoded").
your javascript function :
function testNewPHP(){
var str = "This is test";
xmlhttp = new XMLHttpRequest();
str = "q=" + encodeURIComponent(str);
alert (str);
xmlhttp.open("POST","testpost.php", true);
xmlhttp.onreadystatechange=function(){
if (xmlhttp.readyState == 4){
if(xmlhttp.status == 200){
alert (xmlhttp.responseText);
}
}
};
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send(str);
}
javascript :
function testNewPHP(){
var str = "This is test";
xmlhttp = new XMLHttpRequest();
str = "q=" + encodeURIComponent(str);
alert (str);
xmlhttp.open("POST","testpost.php", true);
xmlhttp.onreadystatechange=function(){
if (xmlhttp.readyState == 4){
if(xmlhttp.status == 200){
alert (xmlhttp.responseText);
}
}
};
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send(str);
}
testpost.php in your home directory :
<?php
var_dump($_POST);
OUTPUT :
array(1) {
["q"]=>
string(12) "This is test"
}
I tried this code :
var xmlHttp = new XMLHttpRequest();
function activecomm(comm_id,a_link_id)
{
var postComm = "id="+encodeURIComponent(comm_id);
var url = 'comments_mgr_proccesser.php';
xmlHttp.open("POST", url, true);
xmlHttp.onreadystatechange = handleInfo(a_link_id);
xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlHttp.setRequestHeader("Content-length", postComm.length);
xmlHttp.setRequestHeader("Connection", "close");
xmlHttp.send(postComm);
}
function handleInfo(a_link_id)
{
if(xmlHttp.readyState == 1)
{
document.getElementById("commactiveresult").innerHTML = 'loading ..';
}
else if(xmlHttp.readyState == 4)
{
var response = xmlHttp.responseText;
document.getElementById("commactiveresult").innerHTML = response;
}
}
When readyState == 1 the contents of the commactiveresult element is updated, but when readyState == 4 nothing is shown in the same element.
Does anyone know what the problem is please?
You're calling the handleInfo function instead of assigning a ready state handler. Try
xmlHttp.onreadystatechange = function (){
handleInfo(a_link_id);
};
I have a problem with the following code.
When I run it in IE8, I get an alert when I have a successful return from the call.
This does not happen in Firefox and Chrome, i.e. I get no alert when running it there.
Everything else works, except that it seems to me like the code section which is supposed to execute once the call is successful fails.
function stuffFile(file, wfid) {
var xmlhttp = new XMLHttpRequest();
if(window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp = new XMLHttpRequest();
} else {// code for IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
var url = "http://someotherserver.page.aspx";
var params = "fileName=" + file + "¶m11=" + wfid;
xmlhttp.open("POST", url, true);
//Send the proper header information along with the request
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.setRequestHeader("Content-length", params.length);
xmlhttp.setRequestHeader("Connection", "close");
xmlhttp.onreadystatechange = function() {//Call a function when the state changes.
//alert('onready');
if(xmlhttp.readyState == 4 && xmlhttp.status == 200) {
var response = jQuery.trim(xmlhttp.responseText);
alert('response ' + response);
}
}
xmlhttp.send(params);
}
You're already using jQuery, you should use its AJAX capabilities. It takes care of creating the XMLHTTPRequest object and all the differences between different browsers, and does a lot of the stuff you are doing manually.
Hello I want to get xml from Google Weather
var xmlhttp;
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp= new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET", "http://www.google.com/ig/api?weather=london&hl=en", true);
xmlhttp.send(null);
xmlDoc=xmlhttp.responseXML;
It`s not working . Thanks
XMLHttpRequest is asynchronous. You need to use a callback. If you don't want to use a full-fledged library, I recommend using Quirksmode's XHR wrapper:
function callback(xhr)
{
xmlDoc = xhr.responseXML;
// further XML processing here
}
sendRequest('http://www.google.com/ig/api?weather=london&hl=en', callback);
If you absolutely insist on implementing this yourself:
// callback is the same as above
var xmlhttp;
if (window.XMLHttpRequest)
{
xmlhttp = new XMLHttpRequest();
}
else
{
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET", "http://www.google.com/ig/api?weather=london&hl=en", true);
xmlhttp.onreadystatechange = function ()
{
if (xmlhttp.readyState != 4) return;
if (xmlhttp.status != 200 && xmlhttp.status != 304) return;
callback(xmlhttp);
};
xmlhttp.send(null);
Edit
As #remi commented:
I think you'll get a cross domain access exception : you can't make an ajax request to an other domain than your page's. no ?
Which is (for the most part) correct. You'll need to use a server-side proxy, or whatever API that Google provides, instead of a regular XHR.
You can't do this via javascript to to it being a cross-domain request. You'd have to do this server-side.
In PHP you'd use CURL.
What you are trying to do can't be done with Javascript.
Ok here is the code :
<html>
<body>
<script type="text/javascript">
var xmlhttp;
var xmlDoc;
function callback(xhr)
{
xmlDoc = xhr.responseXML;
// further XML processing here
}
if (window.XMLHttpRequest)
{
xmlhttp = new XMLHttpRequest();
}
else
{
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET", "http://www.google.com/ig/api?weather=london&hl=en", true);
xmlhttp.onreadystatechange = function ()
{
if (xmlhttp.readyState != 4) return;
if (xmlhttp.status != 200 && xmlhttp.status != 304) return;
callback(xmlhttp);
};
xmlhttp.send(null);
alert(xmlDoc);
</script>
</body>
</html>
It doesn`t returns any errors but alert returns undefined.