Javascript XMLHTTPRequest .classList in response - javascript

How can I check if the response received from XMLHTTPRequest has a particular class or not?
async function swipeAction(currentElementObj) {
var cardId = currentElementObj.getAttribute("value");
var dataString = {'card': cardId};
let response = await new Promise(resolve => {
var xhr = new XMLHttpRequest();
xhr.open("POST", "processes/explore.php", true);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.send(JSON.stringify(dataString));
xhr.onreadystatechange = function() {
if(xhr.readyState == 4 && xhr.status == 200) {
// I WANT TO CHECK SOMETHING LIKE THIS
if(xhr.response.getElementById("matched").classList.contains('matched'))
alert(xhr.response.getElementById("matched").classList);
}
}
});
}
In the response received, I want to check if the element with id matched has a class name matched or not. However, the above code isn't working. What should be the proper approach here?

If you're expecting plain text/html response from the server then processing it may look like that:
async function swipeAction(currentElementObj) {
var cardId = currentElementObj.getAttribute("value");
var dataString = { card: cardId };
let response = await new Promise((resolve, reject) => {
try {
var xhr = new XMLHttpRequest();
xhr.open("POST", "processes/explore.php", true);
xhr.setRequestHeader("Content-Type", "application/json");
// add responseType = "document" for response to be parsed into DOM
xhr.responseType = "document";
// override response mime type (in case your server sends text/plain)
xhr.overrideMimeType("text/html");
xhr.send(JSON.stringify(dataString));
xhr.onreadystatechange = function () {
// check for non-empty responseXML property
if (xhr.readyState == 4 && xhr.status == 200 && xhr.responseXML) {
const matched = xhr.responseXML.getElementById("matched");
if (!matched) return reject("Element not found in response");
if (matched) {
alert(matched.classList.contains("matched"));
resolve(true);
}
} else {
return reject("Incompatible response format");
}
};
} catch (e) {
reject(e.toString());
}
});
}

Related

I want to put a responseText value in a variable in browser

let xhr = new XMLHttpRequest();
xhr.open("GET", "https://reqbin.com/echo/get/json");
xhr.onreadystatechange = () => {
if (xhr.readyState === 4) {
console.log(xhr.responseText);
}
};
xhr.send();
let a = xhr.responseText
Why can't I save the value of variable 'a' right away?
I can not get the value {"success":"true"}
how can i get?
Since this request is happening asynchronously your
let a = xhr.responseText
code is executing before the server returns a response
In that case what you can do is place the code that you want to execute inside onreadystatechange event handler, which will execute after server has returned you a response.
let xhr = new XMLHttpRequest();
let a;
xhr.open("GET", "https://reqbin.com/echo/get/json");
xhr.onreadystatechange = () => {
if (xhr.readyState === 4) {
console.log(xhr.responseText);
a = xhr.responseText
}
};
xhr.send();

XMLHttpRequest return from a function before response is back

I have a function as the code below, I am trying to send a file through XMLHttpRequest to the server and then store it in DB and retrieve the id of the file in DB and make an object of ids.
The problem is that the function exits a lot before I got the response back from the server to store it in the object therefore the object doesn't store those values.
I know that I need make the XHR asynchronous but it doesn't change the result, I have also tried timeout or using a different platform like Ajax but still, it didn't work.
async function getFileObj() {
var FileObject = {}
for (let key1 in PObj) {
FileObject[key1] = {}
for (let key2 in PObj[key1]) {
FileObject[key1][key2] = {}
for (let key3 in PObj[key1][key2]) {
const formData = new FormData();
formData.append('myFile.png', filesObjDB[key1][key2][key3]);
var xhr = new XMLHttpRequest();
xhr.open("POST", 'url', true);
xhr.onreadystatechange = async function() {
if (this.readyState === XMLHttpRequest.DONE && this.status === 200)
var id = await xhr.response.text();
FileObject[key1][key2][key3] = parseInt(id)
}
xhr.responseType = 'blob';
xhr.send(formData);
}
}
}
return FileObject;
}
Help would be very appreciated!
You are not awaiting the request. To make the existing code wait for the result, you'd need to wrap the outdated callback-based code in a promise and await that (and also I don't think getting the response text of an XHR works as you showed, I changed it now):
// This is just to demonstrate what was immediately wrong
// with the existing code - it's not the best solution! See below.
FileObject[key1][key2][key3] = await new Promise((resolve, reject) => {
var xhr = new XMLHttpRequest();
xhr.open("POST", url, true);
xhr.onreadystatechange = function() {
if (this.readyState === XMLHttpRequest.DONE && this.status === 200) {
var id = xhr.responseText;
resolve(parseInt(id));
}
};
xhr.send(formData);
});
Note there is no error handling yet, if the request fails everything will just hang.
But at that point, it doesn't actually make sense to use XHR in the first place! It's a lot more straightforward to use fetch, which has a promise API out of the box:
const response = await fetch(url, { method: 'POST', body: formData })
FileObject[key1][key2][key3] = parseInt(await response.text())

AJAX for reuse with different data? (NO jQuery) [duplicate]

How can I make an AJAX call using JavaScript, without using jQuery?
With "vanilla" (plain) JavaScript:
function loadXMLDoc() {
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == XMLHttpRequest.DONE) { // XMLHttpRequest.DONE == 4
if (xmlhttp.status == 200) {
document.getElementById("myDiv").innerHTML = xmlhttp.responseText;
}
else if (xmlhttp.status == 400) {
alert('There was an error 400');
}
else {
alert('something else other than 200 was returned');
}
}
};
xmlhttp.open("GET", "ajax_info.txt", true);
xmlhttp.send();
}
With jQuery:
$.ajax({
url: "test.html",
context: document.body,
success: function() {
$(this).addClass("done");
}
});
Using the following snippet you can do similar things pretty easily, like this:
ajax.get('/test.php', {foo: 'bar'}, function() {});
Here is the snippet:
var ajax = {};
ajax.x = function () {
if (typeof XMLHttpRequest !== 'undefined') {
return new XMLHttpRequest();
}
var versions = [
"MSXML2.XmlHttp.6.0",
"MSXML2.XmlHttp.5.0",
"MSXML2.XmlHttp.4.0",
"MSXML2.XmlHttp.3.0",
"MSXML2.XmlHttp.2.0",
"Microsoft.XmlHttp"
];
var xhr;
for (var i = 0; i < versions.length; i++) {
try {
xhr = new ActiveXObject(versions[i]);
break;
} catch (e) {
}
}
return xhr;
};
ajax.send = function (url, callback, method, data, async) {
if (async === undefined) {
async = true;
}
var x = ajax.x();
x.open(method, url, async);
x.onreadystatechange = function () {
if (x.readyState == 4) {
callback(x.responseText)
}
};
if (method == 'POST') {
x.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
}
x.send(data)
};
ajax.get = function (url, data, callback, async) {
var query = [];
for (var key in data) {
query.push(encodeURIComponent(key) + '=' + encodeURIComponent(data[key]));
}
ajax.send(url + (query.length ? '?' + query.join('&') : ''), callback, 'GET', null, async)
};
ajax.post = function (url, data, callback, async) {
var query = [];
for (var key in data) {
query.push(encodeURIComponent(key) + '=' + encodeURIComponent(data[key]));
}
ajax.send(url, callback, 'POST', query.join('&'), async)
};
There is now a nicer Fetch API available natively in modern browsers. The fetch() method allows you to make web requests.
For example, to request some JSON from /get-data:
let options = {
method: 'GET',
headers: {}
};
fetch('/get-data', options)
.then(response => response.json())
.then(body => {
// Do something with body
});
See MDN Web Docs: Using the Fetch API for more details.
You can use the following function:
function callAjax(url, callback){
var xmlhttp;
// compatible with IE7+, Firefox, Chrome, Opera, Safari
xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function(){
if (xmlhttp.readyState == 4 && xmlhttp.status == 200){
callback(xmlhttp.responseText);
}
}
xmlhttp.open("GET", url, true);
xmlhttp.send();
}
You can try similar solutions online on these links:
https://www.w3schools.com/xml/tryit.asp?filename=tryajax_first
https://www.w3schools.com/xml/tryit.asp?filename=tryajax_callback
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
alert(this.responseText);
}
};
xhttp.open("GET", "ajax_info.txt", true);
xhttp.send();
How about this version in plain ES6/ES2015?
function get(url) {
return new Promise((resolve, reject) => {
const req = new XMLHttpRequest();
req.open('GET', url);
req.onload = () => req.status === 200 ? resolve(req.response) : reject(Error(req.statusText));
req.onerror = (e) => reject(Error(`Network Error: ${e}`));
req.send();
});
}
The function returns a promise. Here is an example on how to use the function and handle the promise it returns:
get('foo.txt')
.then((data) => {
// Do stuff with data, if foo.txt was successfully loaded.
})
.catch((err) => {
// Do stuff on error...
});
If you need to load a json file you can use JSON.parse() to convert the loaded data into an JS Object.
You can also integrate req.responseType='json' into the function but unfortunately there is no IE support for it, so I would stick with JSON.parse().
Use XMLHttpRequest.
Simple GET request
httpRequest = new XMLHttpRequest()
httpRequest.open('GET', 'http://www.example.org/some.file')
httpRequest.send()
Simple POST request
httpRequest = new XMLHttpRequest()
httpRequest.open('POST', 'http://www.example.org/some/endpoint')
httpRequest.send('some data')
We can specify that the request should be asynchronous(true), the default, or synchronous(false) with an optional third argument.
// Make a synchronous GET request
httpRequest.open('GET', 'http://www.example.org/some.file', false)
We can set headers before calling httpRequest.send()
httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
We can handle the response by setting httpRequest.onreadystatechange to a function before calling httpRequest.send()
httpRequest.onreadystatechange = function(){
// Process the server response here.
if (httpRequest.readyState === XMLHttpRequest.DONE) {
if (httpRequest.status === 200) {
alert(httpRequest.responseText);
} else {
alert('There was a problem with the request.');
}
}
}
You can get the correct object according to the browser with
function getXmlDoc() {
var xmlDoc;
if (window.XMLHttpRequest) {
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlDoc = new XMLHttpRequest();
}
else {
// code for IE6, IE5
xmlDoc = new ActiveXObject("Microsoft.XMLHTTP");
}
return xmlDoc;
}
With the correct object, a GET might can be abstracted to:
function myGet(url, callback) {
var xmlDoc = getXmlDoc();
xmlDoc.open('GET', url, true);
xmlDoc.onreadystatechange = function() {
if (xmlDoc.readyState === 4 && xmlDoc.status === 200) {
callback(xmlDoc);
}
}
xmlDoc.send();
}
And a POST to:
function myPost(url, data, callback) {
var xmlDoc = getXmlDoc();
xmlDoc.open('POST', url, true);
xmlDoc.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlDoc.onreadystatechange = function() {
if (xmlDoc.readyState === 4 && xmlDoc.status === 200) {
callback(xmlDoc);
}
}
xmlDoc.send(data);
}
I was looking for a way to include promises with ajax and exclude jQuery. There's an article on HTML5 Rocks that talks about ES6 promises. (You could polyfill with a promise library like Q) You can use the code snippet that I copied from the article.
function get(url) {
// Return a new promise.
return new Promise(function(resolve, reject) {
// Do the usual XHR stuff
var req = new XMLHttpRequest();
req.open('GET', url);
req.onload = function() {
// This is called even on 404 etc
// so check the status
if (req.status == 200) {
// Resolve the promise with the response text
resolve(req.response);
}
else {
// Otherwise reject with the status text
// which will hopefully be a meaningful error
reject(Error(req.statusText));
}
};
// Handle network errors
req.onerror = function() {
reject(Error("Network Error"));
};
// Make the request
req.send();
});
}
Note: I also wrote an article about this.
A small combination from a couple of the examples below and created this simple piece:
function ajax(url, method, data, async)
{
method = typeof method !== 'undefined' ? method : 'GET';
async = typeof async !== 'undefined' ? async : false;
if (window.XMLHttpRequest)
{
var xhReq = new XMLHttpRequest();
}
else
{
var xhReq = new ActiveXObject("Microsoft.XMLHTTP");
}
if (method == 'POST')
{
xhReq.open(method, url, async);
xhReq.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhReq.setRequestHeader("X-Requested-With", "XMLHttpRequest");
xhReq.send(data);
}
else
{
if(typeof data !== 'undefined' && data !== null)
{
url = url+'?'+data;
}
xhReq.open(method, url, async);
xhReq.setRequestHeader("X-Requested-With", "XMLHttpRequest");
xhReq.send(null);
}
//var serverResponse = xhReq.responseText;
//alert(serverResponse);
}
// Example usage below (using a string query):
ajax('http://www.google.com');
ajax('http://www.google.com', 'POST', 'q=test');
OR if your parameters are object(s) - minor additional code adjustment:
var parameters = {
q: 'test'
}
var query = [];
for (var key in parameters)
{
query.push(encodeURIComponent(key) + '=' + encodeURIComponent(parameters[key]));
}
ajax('http://www.google.com', 'POST', query.join('&'));
Both should be fully browser + version compatible.
If you don't want to include JQuery, I'd try out some lightweight AJAX libraries.
My favorite is reqwest. It's only 3.4kb and very well built out: https://github.com/ded/Reqwest
Here's a sample GET request with reqwest:
reqwest({
url: url,
method: 'GET',
type: 'json',
success: onSuccess
});
Now if you want something even more lightweight, I'd try microAjax at a mere 0.4kb: https://code.google.com/p/microajax/
This is all the code right here:
function microAjax(B,A){this.bindFunction=function(E,D){return function(){return E.apply(D,[D])}};this.stateChange=function(D){if(this.request.readyState==4){this.callbackFunction(this.request.responseText)}};this.getRequest=function(){if(window.ActiveXObject){return new ActiveXObject("Microsoft.XMLHTTP")}else{if(window.XMLHttpRequest){return new XMLHttpRequest()}}return false};this.postBody=(arguments[2]||"");this.callbackFunction=A;this.url=B;this.request=this.getRequest();if(this.request){var C=this.request;C.onreadystatechange=this.bindFunction(this.stateChange,this);if(this.postBody!==""){C.open("POST",B,true);C.setRequestHeader("X-Requested-With","XMLHttpRequest");C.setRequestHeader("Content-type","application/x-www-form-urlencoded");C.setRequestHeader("Connection","close")}else{C.open("GET",B,true)}C.send(this.postBody)}};
And here's a sample call:
microAjax(url, onSuccess);
XMLHttpRequest()
You can use the XMLHttpRequest() constructor to create a new XMLHttpRequest (XHR) object which will allow you to interact with a server using standard HTTP request methods (such as GET and POST):
const data = JSON.stringify({
example_1: 123,
example_2: 'Hello, world!',
});
const request = new XMLHttpRequest();
request.addEventListener('load', function () {
if (this.readyState === 4 && this.status === 200) {
console.log(this.responseText);
}
});
request.open('POST', 'example.php', true);
request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
request.send(data);
fetch()
You can also use the fetch() method to obtain a Promise which resolves to the Response object representing the response to your request:
const data = JSON.stringify({
example_1: 123,
example_2: 'Hello, world!',
});
fetch('example.php', {
method: 'POST',
headers: {
'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8',
},
body: data,
}).then(response => {
if (response.ok) {
response.text().then(response => {
console.log(response);
});
}
});
navigator.sendBeacon()
On the other hand, if you are simply attempting to POST data and do not need a response from the server, the shortest solution would be to use navigator.sendBeacon():
const data = JSON.stringify({
example_1: 123,
example_2: 'Hello, world!',
});
navigator.sendBeacon('example.php', data);
Try using the Fetch Api (Fetch API)
fetch('http://example.com/movies.json').then(response => response.json()).then(data => console.log(data));
Its really clear, and 100% vanilla.
Old but I will try, maybe someone will find this info useful.
This is the minimal amount of code you need to do a GET request and fetch some JSON formatted data. This is applicable only to modern browsers like latest versions of Chrome, FF, Safari, Opera and Microsoft Edge.
const xhr = new XMLHttpRequest();
xhr.open('GET', 'https://example.com/data.json'); // by default async
xhr.responseType = 'json'; // in which format you expect the response to be
xhr.onload = function() {
if(this.status == 200) {// onload called even on 404 etc so check the status
console.log(this.response); // No need for JSON.parse()
}
};
xhr.onerror = function() {
// error
};
xhr.send();
Also check out new Fetch API which is a promise-based replacement for XMLHttpRequest API.
From youMightNotNeedJquery.com + JSON.stringify
var request = new XMLHttpRequest();
request.open('POST', '/my/url', true);
request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
request.send(JSON.stringify(data));
This may help:
function doAjax(url, callback) {
var xmlhttp = window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP");
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
callback(xmlhttp.responseText);
}
}
xmlhttp.open("GET", url, true);
xmlhttp.send();
}
<html>
<script>
var xmlDoc = null ;
function load() {
if (typeof window.ActiveXObject != 'undefined' ) {
xmlDoc = new ActiveXObject("Microsoft.XMLHTTP");
xmlDoc.onreadystatechange = process ;
}
else {
xmlDoc = new XMLHttpRequest();
xmlDoc.onload = process ;
}
xmlDoc.open( "GET", "background.html", true );
xmlDoc.send( null );
}
function process() {
if ( xmlDoc.readyState != 4 ) return ;
document.getElementById("output").value = xmlDoc.responseText ;
}
function empty() {
document.getElementById("output").value = '<empty>' ;
}
</script>
<body>
<textarea id="output" cols='70' rows='40'><empty></textarea>
<br></br>
<button onclick="load()">Load</button>
<button onclick="empty()">Clear</button>
</body>
</html>
Well it is just a 4 step easy proceess,
I hope it helps
Step 1. Store the reference to the XMLHttpRequest object
var xmlHttp = createXmlHttpRequestObject();
Step 2. Retrieve the XMLHttpRequest object
function createXmlHttpRequestObject() {
// will store the reference to the XMLHttpRequest object
var xmlHttp;
// if running Internet Explorer
if (window.ActiveXObject) {
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {
xmlHttp = false;
}
}
// if running Mozilla or other browsers
else {
try {
xmlHttp = new XMLHttpRequest();
} catch (e) {
xmlHttp = false;
}
}
// return the created object or display an error message
if (!xmlHttp)
alert("Error creating the XMLHttpRequest object.");
else
return xmlHttp;
}
Step 3. Make asynchronous HTTP request using the XMLHttpRequest object
function process() {
// proceed only if the xmlHttp object isn't busy
if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0) {
// retrieve the name typed by the user on the form
item = encodeURIComponent(document.getElementById("input_item").value);
// execute the your_file.php page from the server
xmlHttp.open("GET", "your_file.php?item=" + item, true);
// define the method to handle server responses
xmlHttp.onreadystatechange = handleServerResponse;
// make the server request
xmlHttp.send(null);
}
}
Step 4. Executed automatically when a message is received from the server
function handleServerResponse() {
// move forward only if the transaction has completed
if (xmlHttp.readyState == 4) {
// status of 200 indicates the transaction completed successfully
if (xmlHttp.status == 200) {
// extract the XML retrieved from the server
xmlResponse = xmlHttp.responseText;
document.getElementById("put_response").innerHTML = xmlResponse;
// restart sequence
}
// a HTTP status different than 200 signals an error
else {
alert("There was a problem accessing the server: " + xmlHttp.statusText);
}
}
}
in plain JavaScript in the browser:
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
if (xhr.readyState == XMLHttpRequest.DONE ) {
if(xhr.status == 200){
console.log(xhr.responseText);
} else if(xhr.status == 400) {
console.log('There was an error 400');
} else {
console.log('something else other than 200 was returned');
}
}
}
xhr.open("GET", "mock_data.json", true);
xhr.send();
Or if you want to use Browserify to bundle your modules up using node.js. You can use superagent:
var request = require('superagent');
var url = '/mock_data.json';
request
.get(url)
.end(function(err, res){
if (res.ok) {
console.log('yay got ' + JSON.stringify(res.body));
} else {
console.log('Oh no! error ' + res.text);
}
});
Here's a JSFiffle without JQuery
http://jsfiddle.net/rimian/jurwre07/
function loadXMLDoc() {
var xmlhttp = new XMLHttpRequest();
var url = 'http://echo.jsontest.com/key/value/one/two';
xmlhttp.onreadystatechange = function () {
if (xmlhttp.readyState == XMLHttpRequest.DONE) {
if (xmlhttp.status == 200) {
document.getElementById("myDiv").innerHTML = xmlhttp.responseText;
} else if (xmlhttp.status == 400) {
console.log('There was an error 400');
} else {
console.log('something else other than 200 was returned');
}
}
};
xmlhttp.open("GET", url, true);
xmlhttp.send();
};
loadXMLDoc();
var load_process = false;
function ajaxCall(param, response) {
if (load_process == true) {
return;
}
else
{
if (param.async == undefined) {
param.async = true;
}
if (param.async == false) {
load_process = true;
}
var xhr;
xhr = new XMLHttpRequest();
if (param.type != "GET") {
xhr.open(param.type, param.url, true);
if (param.processData != undefined && param.processData == false && param.contentType != undefined && param.contentType == false) {
}
else if (param.contentType != undefined || param.contentType == true) {
xhr.setRequestHeader('Content-Type', param.contentType);
}
else {
xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
}
}
else {
xhr.open(param.type, param.url + "?" + obj_param(param.data));
}
xhr.onprogress = function (loadTime) {
if (param.progress != undefined) {
param.progress({ loaded: loadTime.loaded }, "success");
}
}
xhr.ontimeout = function () {
this.abort();
param.success("timeout", "timeout");
load_process = false;
};
xhr.onerror = function () {
param.error(xhr.responseText, "error");
load_process = false;
};
xhr.onload = function () {
if (xhr.status === 200) {
if (param.dataType != undefined && param.dataType == "json") {
param.success(JSON.parse(xhr.responseText), "success");
}
else {
param.success(JSON.stringify(xhr.responseText), "success");
}
}
else if (xhr.status !== 200) {
param.error(xhr.responseText, "error");
}
load_process = false;
};
if (param.data != null || param.data != undefined) {
if (param.processData != undefined && param.processData == false && param.contentType != undefined && param.contentType == false) {
xhr.send(param.data);
}
else {
xhr.send(obj_param(param.data));
}
}
else {
xhr.send();
}
if (param.timeout != undefined) {
xhr.timeout = param.timeout;
}
else
{
xhr.timeout = 20000;
}
this.abort = function (response) {
if (XMLHttpRequest != null) {
xhr.abort();
load_process = false;
if (response != undefined) {
response({ status: "success" });
}
}
}
}
}
function obj_param(obj) {
var parts = [];
for (var key in obj) {
if (obj.hasOwnProperty(key)) {
parts.push(encodeURIComponent(key) + '=' + encodeURIComponent(obj[key]));
}
}
return parts.join('&');
}
my ajax call
var my_ajax_call=ajaxCall({
url: url,
type: method,
data: {data:value},
dataType: 'json',
async:false,//synchronous request. Default value is true
timeout:10000,//default timeout 20000
progress:function(loadTime,status)
{
console.log(loadTime);
},
success: function (result, status) {
console.log(result);
},
error :function(result,status)
{
console.log(result);
}
});
for abort previous requests
my_ajax_call.abort(function(result){
console.log(result);
});
HTML :
<!DOCTYPE html>
<html>
<head>
<script>
function loadXMLDoc()
{
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.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("myDiv").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","1.php?id=99freebies.blogspot.com",true);
xmlhttp.send();
}
</script>
</head>
<body>
<div id="myDiv"><h2>Let AJAX change this text</h2></div>
<button type="button" onclick="loadXMLDoc()">Change Content</button>
</body>
</html>
PHP:
<?php
$id = $_GET[id];
print "$id";
?>
A verry good solution with pure javascript is here
/*create an XMLHttpRequest object*/
let GethttpRequest=function(){
let httpRequest=false;
if(window.XMLHttpRequest){
httpRequest =new XMLHttpRequest();
if(httpRequest.overrideMimeType){
httpRequest.overrideMimeType('text/xml');
}
}else if(window.ActiveXObject){
try{httpRequest =new ActiveXObject("Msxml2.XMLHTTP");
}catch(e){
try{
httpRequest =new ActiveXObject("Microsoft.XMLHTTP");
}catch(e){}
}
}
if(!httpRequest){return 0;}
return httpRequest;
}
/*Defining a function to make the request every time when it is needed*/
function MakeRequest(){
let uriPost ="myURL";
let xhrPost =GethttpRequest();
let fdPost =new FormData();
let date =new Date();
/*data to be sent on server*/
let data = {
"name" :"name",
"lName" :"lName",
"phone" :"phone",
"key" :"key",
"password" :"date"
};
let JSONdata =JSON.stringify(data);
fdPost.append("data",JSONdata);
xhrPost.open("POST" ,uriPost, true);
xhrPost.timeout = 9000;/*the time you need to quit the request if it is not completed*/
xhrPost.onloadstart = function (){
/*do something*/
};
xhrPost.onload = function (){
/*do something*/
};
xhrPost.onloadend = function (){
/*do something*/
}
xhrPost.onprogress =function(){
/*do something*/
}
xhrPost.onreadystatechange =function(){
if(xhrPost.readyState < 4){
}else if(xhrPost.readyState === 4){
if(xhrPost.status === 200){
/*request succesfull*/
}else if(xhrPost.status !==200){
/*request failled*/
}
}
}
xhrPost.ontimeout = function (e){
/*you can stop the request*/
}
xhrPost.onerror = function (){
/*you can try again the request*/
};
xhrPost.onabort = function (){
/*you can try again the request*/
};
xhrPost.overrideMimeType("text/plain; charset=x-user-defined-binary");
xhrPost.setRequestHeader("Content-disposition", "form-data");
xhrPost.setRequestHeader("X-Requested-With","xmlhttprequest");
xhrPost.send(fdPost);
}
/*PHP side
<?php
//check if the variable $_POST["data"] exists isset() && !empty()
$data =$_POST["data"];
$decodedData =json_decode($_POST["data"]);
//show a single item from the form
echo $decodedData->name;
?>
*/
/*Usage*/
MakeRequest();
Fast code fetch without jQuery
async function product_serach(word) {
var response = await fetch('<?php echo base_url(); ?>home/product_search?search='+word);
var json = await response.json();
for (let [key, value] of Object.entries(json))
{
console.log(json)
}
}

Returning original post data if request fails

I know I could just do this with a global, but I'd like to be object oriented if I can. If my request response returns a false for that 'ok' value, I'd like to log the data that was originally posted. Is that data accessible by a listener function on the request object?
Thanks!
function reqListener () {
var data = this.responseText;
var jsonResponse = JSON.parse(data);
if (jsonResponse['ok'] == false) {
//Here I want to log the data that I originally posted
console.log(__TheFormDataThatWasPassedtoSend__);
}
}
var xhr = new XMLHttpRequest();
xhr.addEventListener("load",reqListener);
xhr.open('POST',urltopostto, true);
// Set up a handler for when the request finishes.
xhr.onload = function () {
if (xhr.status === 200) {
// File(s) uploaded.
console.log('Uploaded');
} else {
alert('An error occurred!');
}
};
xhr.send(formData);
So the problem you have is needing to use data known when you create the eventListener when the eventListener actually fires. Below is your code to do this with formData
function reqListener (formData) {
var data = this.responseText;
var jsonResponse = JSON.parse(data);
if (jsonResponse['ok'] == false) {
console.log(formData);
}
}
var xhr = new XMLHttpRequest();
xhr.addEventListener("load", function() { reqListener.call(this,formData) });
xhr.open('POST',urltopostto, true);
// Set up a handler for when the request finishes.
xhr.onload = function () {
if (xhr.status === 200) {
// File(s) uploaded.
console.log('Uploaded');
} else {
alert('An error occurred!');
}
};
xhr.send(formData);

How to handle XMLHttpRequests in a redux action?

I have a redux-form that is passing props to my action. The property this.props.userImages[0] is an image file from a file input on that form. I'm then taking that image and making and XMLHttpRequest to Cloudinary which generates a url for that image. Once I receive the url data (xhr.responseText), I'd like to then merge it with my other props to that I can then post all of my props to an API (all form info + newly created image URL).
I know that I have to wait for my request to generate a url to resolve, but having issues with getting it right before I can pass it onto my other function which can take that info and merge it in with props before posting to my API.
//..
function generateUrl(props) {
// Grabs image file from my form's file input and uploads
// to cloudinary service so that a URL can be generated
const cloudinaryURL = 'https://api.cloudinary.com/v1_1/<my_name>/image/upload';
const apiKey = 'secret_key';
const uploadPreset = 'test_preset';
const data = new FormData();
data.append('file', props.userImages[0]);
data.append('upload_preset', uploadPreset);
data.append('api_key', apiKey);
const xhr = new XMLHttpRequest();
xhr.open('POST', cloudinaryURL, true);
xhr.send(data);
xhr.onReadyStateChange = () => {
if (xhr.readyState == 4 && xhr.status == 200) {
return JSON.parse(xhr.responseText);
}
};
return xhr.onReadyStateChange();
}
export function createReview(props) {
const imageUrl = generateUrl(props);
const mergedProps = //...
// Here I'd like to merge my newly generated
// url back into props before I post to my API like so...
const request = axios.post(`${REQUEST_URL}/api`, mergedProps)
return {
type: CREATE_REVIEW,
payload: request
}
};
Any and all help is greatly appreciated.
This has nothing to do with promises in the context of your example XMLHttpRequest based code.
The assumption your making is that the callback assigned to onReadyStateChange does something with it's return value. Instead anything returned from that function is dutifully ignored.
What you want is to pass the value onward through another callback.
function generateUrl(props, callback) {
// Do things here
xhr.onReadyStateChange = () => {
if (xhr.readyState == 4 && xhr.status == 200) {
callback(JSON.parse(xhr.responseText));
}
};
}
generateUrl(props, (response) => {
const mergedProps = // Use response as expected.
});
Since you mentioned promise and your using ES2015 we can convert this to actually use promises which is probably what you wanted to begin with.
function generateUrl(props) {
return new Promise((resolve, reject) => {
const cloudinaryURL = 'https://api.cloudinary.com/v1_1/<my_name>/image/upload';
const apiKey = 'secret_key';
const uploadPreset = 'test_preset';
const data = new FormData();
data.append('file', props.userImages[0]);
data.append('upload_preset', uploadPreset);
data.append('api_key', apiKey);
const xhr = new XMLHttpRequest();
xhr.onReadyStateChange = () => {
if (xhr.readyState == 4) {
if (xhr.status == 200) {
resolve(xhr.responseText);
} else {
reject(new Error(`Failed HTTP request (${xhr.status})`));
}
};
xhr.onerror = reject;
xhr.open('POST', cloudinaryURL, true);
xhr.send(data);
});
}
generateUrl(props)
.then(JSON.parse)
.then(results => {
// Do something with response
})
.catch(error => {
// Do something with the error
});

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