I want to make a JS Ajax request but it doesn't work.
I wrote this code:
var i=0;
function send()
{
var request = new XMLHttpRequest();
request.open("GET", 'support.html', true);
request.send(null);
request.onreadystatechange = interpretRequest;
i++;
document.getElementById("debug").innerHTML=document.getElementById("debug").innerHTML+i;
}
function interpretRequest() {
document.getElementById("answer").innerHTML=document.getElementById("answer").innerHTML+"answer received";
document.getElementById("answer").innerHTML=document.getElementById("answer").innerHTML+request.status;
document.getElementById("answer").innerHTML=document.getElementById("answer").innerHTML+request.readyState;
switch (request.readyState) {
// if readyState == 4 and status == 200
case 4:
document.getElementById("Antwort").innerHTML=document.getElementById("Antwort").innerHTML+" answer received and state 4";
if (request.status != 200) {
alert("Error"+request.status);
} else {
var content = request.responseText;
// write content
document.getElementById("content").innerHTML = content;
}
break;
default:
break;
}
}
The function send is called by an intervall every s.I see that this works because
the nummers appears in the debug div. The function interpretRequest is called too. The string "answer received" appears but there is no print out which contains the request.status. In addition case 4 is never entered and the content div stays empty.
The HTML File is:
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Test</title>
<script type="text/javascript" src="code.js"></script>
</head>
<body>
<div id="debug">Debug:</div>
<br /><hr />
<div id="content">HTML:</div>
<br /><hr />
<div id="answer">answer:</div>
</body>
</html>
The support.html is in the same folder and it contains:
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h3>It works It works It works It works It workIt works</h3>
</body>
</html>
request isn't a global, so you can't access it from the interpretRequest function.
Use this instead.
Related
I had similar code run before but now i've lost it. No matter what I do, it will never run the php code.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script>
function kosarica() {
var vrednost = "Itworks!";
var httpr=new XMLHttpRequest();
httpr.open("POST","izpis3.php",true);
httpr.setRequestHeader("Content-type","aplication/x-www-form-urlencode");
httpr.onreadystatechange=function(){
if(httpr.readyState==4 && httpr.status ==200){
document.getElementById("responce").innerHTML=httpr.responseText;
}
httpr.send("vrednost"+vrednost);
}
}
</script>
</head>
<body>
<p id="responce">a</p>
<button onclick="kosarica()">Click me</button>
</body>
</html>
PHP Code:
<?php
echo $_POST['vrednost'];
?>
I know that I can make code for this example all in javascript but I want to run more php code where it access my database.
It does not fail, but it does never happen. You need to move the send() outside the handler.
The content type is wrong.
You need to use an equal sign to make it a variable for PHP.
Please do not use var keyword. Use const for a constant or let for a variable.
function kosarica() {
const vrednost = "Itworks!";
const httpr = new XMLHttpRequest();
httpr.open("POST", "izpis3.php", true);
httpr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
httpr.onreadystatechange = function () {
if (httpr.readyState === 4 && httpr.status === 200) {
document.getElementById("responce").innerHTML = httpr.responseText;
}
}
httpr.send("vrednost=" + vrednost);
}
We have an Ember (3.5) application. For technical reasons we need environment variables to be set on page load, as opposed to build time. We're trying to set them in index.html the following way:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>App</title>
<meta name="description" content="">
<meta name="viewport" content="width=device-width, initial-scale=1">
{{content-for "head"}}
<script type="application/javascript">
// Object.assign polyfill
Object.assign||Object.defineProperty(Object,"assign",{enumerable:!1,configurable:!0,writable:!0,value:function(e,r){"use strict";if(null==e)throw new TypeError("Cannot convert first argument to object");for(var t=Object(e),n=1;n<arguments.length;n++){var o=arguments[n];if(null!=o)for(var a=Object.keys(Object(o)),c=0,b=a.length;c<b;c++){var i=a[c],l=Object.getOwnPropertyDescriptor(o,i);void 0!==l&&l.enumerable&&(t[i]=o[i])}}return t}});
window.env = {};
var request = new XMLHttpRequest();
request.open('GET', '/api/frontend_settings', true);
request.send(null);
request.addEventListener('readystatechange', () => {
if (request.status === 200) {
if (request.readyState === 4) {
Object.assign(window.env, JSON.parse(request.response).settings);
}
}
}, false);
</script>
<link integrity="" rel="stylesheet" href="{{rootURL}}assets/vendor.css">
<link integrity="" rel="stylesheet" href="{{rootURL}}assets/app-frontend.css">
{{content-for "head-footer"}}
</head>
<body>
<script integrity="" src="{{rootURL}}assets/vendor.js"></script>
<script integrity="" src="{{rootURL}}assets/app-frontend.js"></script>
</body>
</html>
We added a script which makes a request to some endpoint (/api/frontend_env_vars) in the snippet. This endpoint responds with a JSON with the key-values of environment variables which we then assign to window.env.
The problem we have is that sometimes Ember scripts load before the variables have been assigned (since we do a request that takes some time to complete), which makes the application crash.
We tried the following alteration to the script, but it didn't work (the error was different, though):
<script type="application/javascript">
// Object.assign polyfill
Object.assign||Object.defineProperty(Object,"assign",{enumerable:!1,configurable:!0,writable:!0,value:function(e,r){"use strict";if(null==e)throw new TypeError("Cannot convert first argument to object");for(var t=Object(e),n=1;n<arguments.length;n++){var o=arguments[n];if(null!=o)for(var a=Object.keys(Object(o)),c=0,b=a.length;c<b;c++){var i=a[c],l=Object.getOwnPropertyDescriptor(o,i);void 0!==l&&l.enumerable&&(t[i]=o[i])}}return t}});
window.env = {};
var request = new XMLHttpRequest();
request.open('GET', '/api/frontend_env_vars', true);
request.send(null);
function loadScript(src) {
const script = document.createElement('script');
script.src = src;
document.body.append(script);
}
request.addEventListener('readystatechange', () => {
if (request.status === 200) {
if (request.readyState === 4) {
Object.assign(window.env, JSON.parse(request.response).settings);
loadScript('assets/vendor.js');
loadScript('assets/app-frontend.js');
}
}
}, false);
</script>
We accomplish this using ember-cli-server-variables
Which allows you to define variables in index.html
<html>
<head>
<meta name='your-app-token' content='example:app:token'>
<meta name='your-app-user-location' content='Denver'>
<meta name='your-app-json-data' content='{"foo":"bar"}'>
</head>
</html>
and then access them from the application.
We build our index.html on the server with the needed variables to there is no async needed to fetch them.
I am trying to implement an ajax with simple txt file but the file won't load any suggestion
the html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<script src="app.js"></script>
<title>Ajax 1 - Text File</title>
</head>
<body>
<button id="button" onclick="loadText()">Get Text File</button>
</body>
</html>
and the javascript file:
//Create event Listener of the Get Text File
function loadText(){
// Create XHR object
var xhr = new XMLHttpRequest();
// OPEN - type, url/fileName, async
//console.log(xhr);
xhr.open('GET', 'sample.txt', true);
xhr.onload = function(){
//HTTP statuses
//200: OK
//403: Forbiden
//404: Not Found
if(this.status == 200){
console.log(this.responseText);
}
//Send Request
xhr.send();
}
}
and this is the sample.txt file
This massage form the text file just to ensure you have the ability to
access the text file. so if you do good for you otherwise just keep
trying
Note, I'm trying to achieve it using vanilla javascript without any frameworks or library
As an output I get nothing once I click the button and even in the network tab in the inspector the txt file never even load.
Note, I'm using live sever on vscode
xhr.send() should be outside xhr.onload()
xhr.onload() is the callback function to be executed when the request completes successfully.
refer the docs here https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequestEventTarget/onload
and the javascript file:
//Create event Listener of the Get Text File
function loadText(){
// Create XHR object
var xhr = new XMLHttpRequest();
// OPEN - type, url/fileName, async
//console.log(xhr);
xhr.open('GET', 'sample.txt', true);
xhr.onload = function(){
//HTTP statuses
//200: OK
//403: Forbiden
//404: Not Found
if(this.status == 200){
console.log(this.responseText);
}
//Send Request
}
xhr.send();
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<script src="app.js"></script>
<title>Ajax 1 - Text File</title>
</head>
<body>
<button id="button" onclick="loadText()">Get Text File</button>
</body>
</html>
Here's my code.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>News Site</title>
<script>
window.document.onload = function () {
var xhttp = new XMLHttpRequest();
xhttp.open("GET", "cdcatalog.xml", true);
xhttp.send();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
var xmlDoc = this.responseXML;
console.log(xmlDoc);
document.getElementById("demo").innerHTML = xmlDoc.getElementsByTagName("TITLE")[0].childNodes[0].nodeValue + "<br/>" + xmlDoc.getElementsByTagName("PRICE")[0].childNodes[0].nodeValue;
} else {
document.getElementById("demo").innerHTML = "Can't show it.";
}
}
}
</script>
</head>
<body>
<div id="demo"></div>
</body>
</html>
I am a beginner in using Ajax and this is my first project. I checked with the format, even validated it with W3 Validator, and it doesn't seem to work.
Nothing is showing on the page. It's completely blank.
Can anyone point out my mistake please?
The document object does not have an onload property. Using that style of event handler assignment, you are looking for window.onload.
I have seen questions and answers regarding this issue. For example How to return a HTML file as the response to a POST request? but am having problems implementing the solutions. Here is a sample of some php code in a directory called websiteIssue that does not work, and I am not sure why.
index.php
<?php
if(isset($_POST['page']))
{
$page = $_POST['page'];
}
else
{
$page = "";
}
include 'case.php';
?>
case.php
<?php
$testLog = 'testLog.txt';
$fileHandle = fopen('testLog.txt', 'a');
fwrite($fileHandle, '$page = '.$page."\n";
switch($page)
{
case "screen2":
include 'screen2.php';
fwrite($fileHandle, 'including screen2.php'."\n");
break;
default:
include 'screen1.php';
fwrite($fileHandle, 'including screen1.php'."\n");
break;
}
fclose($fileHandle);
?>
screen1.php
<!DOCTYPE html>
<html lang="en">
<head>
<title>screen1.php</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
</head>
<body>
<button type="button" onClick=dataSubmit({page:"screen2"})> Screen 1 => Screen2</button>
<script>
function dataSubmit(data)
{
var xmlRequest = new XMLHttpRequest();
var formData= new FormData();
for(name in data)
{
formData.append(name, data[name]);
}
xmlRequest.open('POST', 'http://localhost/websiteIssue/');
xmlRequest.send(formData);
}
</script>
</body>
</html>
screen2.php
<!DOCTYPE html>
<html lang="en">
<head>
<title>screen2.php</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
</head>
<body>
<button type="button" onClick=dataSubmit({page:"screen1"})> Screen 2 => Screen1</button>
<script>
function dataSubmit(data)
{
var xmlRequest = new XMLHttpRequest();
var formData= new FormData();
for(name in data)
{
formData.append(name, data[name]);
}
xmlRequest.open('POST', 'http://localhost/websiteIssue/');
xmlRequest.send(formData);
}
</script>
</body>
</html>
On initial load it works as I expected, the html in screen1.php is shown in the browser, but when the button on the page is pressed the html remains the same, rather than changing to that in screen2.php
The output to testText.log is something like:
$page =
including screen1.php
$page = screen2
including screen2.php
As is might be obvious, I am a newbie to this, and hopefully there is some basic thing I have not done. The browser I am running it on is Firefox. Any help would be much appreciated.
Small note:I retyped the code by hand for this post, and have not run it (the machine running the webserver is not connected to the internet), hopefully there are no syntax errors, but I may have made a typo somewhere.
By including the php file you are responding to the javascript, but you arent actually using that response for anything. If redirecting to that page is what you want, you need to use location.assign on the response. To do that:
function dataSubmit(data)
{
var xmlRequest = new XMLHttpRequest();
var formData= new FormData();
// Redirects user to response when received.
xmlRequest.onreadystatechange=function{
if (xmlRequest.readyState == 4 && xmlRequest.status == 200) {
location.assign(xmlRequest.responseText);
}
};
for(name in data)
{
formData.append(name, data[name]);
}
xmlRequest.open('POST', 'http://localhost/websiteIssue/');
xmlRequest.send(formData);
}
Based on the answer given by Felipe Souza I made the following modifications to allow the page to be dynamically modified rather than being a redirect. Thought I would share as it is another solution which some might be interested in.
index.php
<?php
if(isset($_POST['page']))
{
$page = $_POST['page'];
include 'case.php';
}
else
{
include 'base.php';
}
?>
case.php
<?php
switch($page)
{
case "screen2":
include('screen2.php');
break;
case "screen1":
include('screen1.php');
break;
default:
include('screen1.php');
break;
}
?>
base.php
<!DOCTYPE html>
<html lang="en">
<head>
<title>base.php</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
</head>
<body>
<div id="container" style="width:100%; height:100%">
<?php
if(!isset($_POST['page']))
{
$page = "";
include 'case.php';
}
?>
</div>
<script>
function dataSubmit(data)
{
var xmlRequest = new XMLHttpRequest();
var formData = new FormData();
xmlRequest.onreadystatechange=function()
{
if(xmlRequest.readyState==4 && xmlRequest.status==200)
{
document.getElementById("container").innerHTML = xmlRequest.responseText;
}
}
for(name in data)
{
formData.append(name, data[name]);
console.log(name + ":" + data[name]);
}
xmlRequest.open('POST', 'http://localhost/websiteIssue/');
xmlRequest.send(formData);
}
</script>
</body>
</html>
screen1.php
<button type"button" onClick=dataSubmit({page:"screen2"})> Screen 1 => Screen 2</button>
screen2.php
<button type"button" onClick=dataSubmit({page:"screen1"})>Screen 2 => Screen 1</button>
There seem some potential advantages in that the amount of data sent for the new screens is smaller, and (not sure if it is useful) the structure of the website is more disguised. Anyway, it is based on the answer given by Felipe Souza and supplements it (shows a dynamic approach rather than a changing pages one). Just thought I would mention it, if that was what some were looking for.