Develop Reference

JavaScript helps with conditional syntax

I have a function that calls an API (let's call it API-1) to get the song lyrics.
Since this API sometimes can't find a song in its database, I want to call another API (let's call it API-2) to do the same search.
I need to integrate the code of both APIs inside the function, when the first one doesn't get data.
I tell you some very important information:
In API-1 I must force the data to be fetched as XML and the responseType must be 'document'.
API-2 does not require any of the above conditions, the data is parced as JSON and the responseType it supports is 'text', but does not require it to be set, with 'document' it DOES NOT work, it gives error.
Now I will share the function code for API-1 and then I will share the same function code for API-2.
They both work perfect if I test them independently.
The help I am asking for is to integrate API-2 when API-1 does not fetch data.
Code using API-1
this.refreshLyric = function (currentSong, currentArtist) {
var xhr = new XMLHttpRequest;
xhr.open('GET', proxy_URL + api_URL + 'apiv1.asmx/SearchLyricDirect?artist=' + currentArtistE + '&song=' + ucwords(currentSongE), true);
// ONLY FOR THIS XMLHttpRequest responseType must be empty string or 'document'
xhr.responseType = 'document';
// ONLY FOR THIS XMLHttpRequest force the response to be parsed as XML
xhr.overrideMimeType('text/xml');
xhr.onload = function () {
if (xhr.readyState === xhr.DONE && xhr.status === 200) {
var openLyric = document.getElementsByClassName('lyrics')[0];
var lyric = xhr.responseXML.getElementsByTagName('Lyric')[0].innerHTML;
//check if any data was obtained
if (lyric != '') {
document.getElementById('lyric').innerHTML = lyric.replace(/\n/g, '<br />');
openLyric.style.opacity = "1";
openLyric.setAttribute('data-toggle', 'modal');
} else { /////// HERE INTEGRATE API-2 //////
openLyric.style.opacity = "0.3";
openLyric.removeAttribute('data-toggle');
var modalLyric = document.getElementById('modalLyrics');
modalLyric.style.display = "none";
modalLyric.setAttribute('aria-hidden', 'true');
(document.getElementsByClassName('modal-backdrop')[0]) ? document.getElementsByClassName('modal-backdrop')[0].remove(): '';
}
} else {
document.getElementsByClassName('lyrics')[0].style.opacity = "0.3";
document.getElementsByClassName('lyrics')[0].removeAttribute('data-toggle');
}
};
xhr.send();
}
The same code using API-2
this.refreshLyric = function (currentSong, currentArtist) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function () {
if (this.readyState === 4 && this.status === 200) {
var data = JSON.parse(this.responseText);
var openLyric = document.getElementsByClassName('lyrics')[0];
var lyric = data.mus[0].text;
//check if any data was obtained
if (lyric != '') {
document.getElementById('lyric').innerHTML = lyric.replace(/\n/g, '<br />');
openLyric.style.opacity = "1";
openLyric.setAttribute('data-toggle', 'modal');
} else {
openLyric.style.opacity = "0.3";
openLyric.removeAttribute('data-toggle');
var modalLyric = document.getElementById('modalLyrics');
modalLyric.style.display = "none";
modalLyric.setAttribute('aria-hidden', 'true');
(document.getElementsByClassName('modal-backdrop')[0]) ? document.getElementsByClassName('modal-backdrop')[0].remove(): '';
}
} else {
document.getElementsByClassName('lyrics')[0].style.opacity = "0.3";
document.getElementsByClassName('lyrics')[0].removeAttribute('data-toggle');
}
}
xhttp.open('GET', 'https://api.vagalume.com.br/search.php?apikey=' + API_KEY + '&art=' + currentArtist + '&mus=' + currentSong.toLowerCase(), true);
xhttp.send()
}
The shared codes are of the SAME function (this.refreshLyric), what has to be integrated is only the XMLHttpRequest API.
In the ELSE of line 23 of API-1 I must integrate the code of API-2.
I have already tried it in several ways but I am presented with syntax problems with the IF - ELSE conditionals and errors with the API-2 which is getting the responseType and the MimeType of API-1.

EDIT
FIXED: When API-1 cannot find the lyric, I have created a new function that calls API-2. refreshLyric2(currentSong, currentArtist); :)
this.refreshLyric = function (currentSong, currentArtist) {
var xhr = new XMLHttpRequest;
xhr.open('GET', proxy_URL + api_URL + 'apiv1.asmx/SearchLyricDirect?artist=' + currentArtistE + '&song=' + ucwords(currentSongE), true);
// ONLY FOR THIS XMLHttpRequest responseType must be empty string or 'document'
xhr.responseType = 'document';
// ONLY FOR THIS XMLHttpRequest force the response to be parsed as XML
xhr.overrideMimeType('text/xml');
xhr.onload = function () {
if (xhr.readyState === xhr.DONE && xhr.status === 200) {
var openLyric = document.getElementsByClassName('lyrics')[0];
var lyric = xhr.responseXML.getElementsByTagName('Lyric')[0].innerHTML;
//check if any data was obtained
if (lyric != '') {
document.getElementById('lyric').innerHTML = lyric.replace(/\n/g, '<br />');
openLyric.style.opacity = "1";
openLyric.setAttribute('data-toggle', 'modal');
} else {
//If lyric was not obtained, we call API-2
refreshLyric2(currentSong, currentArtist);
}
} else {
document.getElementsByClassName('lyrics')[0].style.opacity = "0.3";
document.getElementsByClassName('lyrics')[0].removeAttribute('data-toggle');
}
};
xhr.send();
}
refreshLyric2 = function (currentSong, currentArtist) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function () {
if (this.readyState === 4 && this.status === 200) {
var data = JSON.parse(this.responseText);
var openLyric = document.getElementsByClassName('lyrics')[0];
var lyric = data.mus[0].text;
//check if any data was obtained
if (lyric != '') {
document.getElementById('lyric').innerHTML = lyric.replace(/\n/g, '<br />');
openLyric.style.opacity = "1";
openLyric.setAttribute('data-toggle', 'modal');
} else {
openLyric.style.opacity = "0.3";
openLyric.removeAttribute('data-toggle');
var modalLyric = document.getElementById('modalLyrics');
modalLyric.style.display = "none";
modalLyric.setAttribute('aria-hidden', 'true');
(document.getElementsByClassName('modal-backdrop')[0]) ? document.getElementsByClassName('modal-backdrop')[0].remove(): '';
}
} else {
document.getElementsByClassName('lyrics')[0].style.opacity = "0.3";
document.getElementsByClassName('lyrics')[0].removeAttribute('data-toggle');
}
}
xhttp.open('GET', 'https://api.vagalume.com.br/search.php?apikey=' + API_KEY + '&art=' + currentArtist + '&mus=' + currentSong.toLowerCase(), true);
xhttp.send()
}

How to pass a string in url in Javascript?

I'm trying to make an application that accesses different sites inside of an iframe from a private JSON dns server.
I have completed the main code, but now I am trying to make it able to be accessed through the url. (Ex. https://thissite.info?url='test.json'&dnsserver='https://thissite.info')
I also want it to default to a value if the variable is not defined in the url. For this, I'm using the following code:
function setup(){
var dns = document.getElementById("dns");
var urlbar = document.getElementById("urlbar");
var frame = document.getElementById("viewport");
if (typeof url === "undefined") {
url = 'Welcome Page URL Here';
} else {
urlbar.value = url;
}
if (typeof dnsserver === "undefined") {
dnsserver = 'Default Server Here';
} else {
dns.value = dnsserver;
}
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
console.log(this.status)
if(this.readyState == 4 && this.status == 200){
var response = JSON.parse(this.responseText);
frame.src=response;
console.log("Request Completed with 200");
};
if(this.readyState == 4 && this.status == 404){
console.log("Website Not Found");
frame.src='404.html'
};
}
xmlhttp.open("GET",dnsserver + url + '.json', true);
xmlhttp.send();
console.log("Request Sent");
}
But even if I pass the vars in the URL, it doesn't accept it.

<script type="text/javascript"> $(function () { $("#btnQueryString").bind("click", function () { var url = "Page2.htm?name=" + encodeURIComponent($("#txtName").val()) + "&technology=" + encodeURIComponent($("#ddlTechnolgy").val()); window.location.href = url; }); }); </script> <input type="button" id="btnQueryString

Using Ajax/XMLhttprequest to send data to a php file with mail function

I have been following this tutorial (https://developer.mozilla.org/en-US/docs/AJAX/Getting_Started) but I had no luck. I am trying to communicate with a php file with a javascript file using XMLhttpRequest. This is the code bellow. I still dont understand how to fully transfer the data across.
HTML
form id="uDF" method="post" onsubmit="submitValidation()">
JavaScript
function submitValidation(){
var data = [document.forms ["uDF"] ["uDFName"].value, document.forms ["uDF"] ["uDFNumber"].value,
document.forms ["uDF"] ["uDFEmail"].value, document.forms ["uDF"] ["uDFSubject"].value,
document.forms ["uDF"] ["uDFMessage"].value,]
console.log(data);
var char = ''; // variable used to check whether email has #
var x;
var isEmail = false;
var isNotEmpty = false;
//for loop checks email for # char
for(x = 0; x<data[2].length;x++)
{
char = data[2].charAt(x);
if(char === "#"){
isEmail = true;
break;
}
}
var i;
//for loop check if data is collected
for(i=0;i < 5;i++){
if(data[i] === ""){
isNotEmpty = false;
}else{
isNotEmpty = true;
}
}
if(isEmail === true && isNotEmpty === true)
{
var httpRequest;
httpRequest = new XMLHttpRequest();
if(!httpRequest){
return false;
}
httpRequest.onreadystatechange = function(){
if(httpRequest.readyState === XMLHttpRequest.DONE && httpRequest.status === 200)
{
var response = JSON.parse(httpRequest.responseText);
}
httpRequest.open('POST', '../userData.mail.php')
httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
httpRequest.send('uDFName=' + encodeURIComponent(data[0]) + 'uDFNumber=' + encodeURIComponent(data[1]) + 'uDFNumber=' + encodeURIComponent(data[3])
+ 'uDFNumber=' + encodeURIComponent(data[4]))
}
}else if (!isNotEmpty){
alert("empty fields");
}else if(!isEmail){
alert("Please enter valid email!");
}
}
PHP
$uDFName = (isset($_POST['uDFName'])) ? $_POST['uDFName'] : '';
$uDFNumber = (isset($_POST['uDFNumber'])) ? $_POST['uDFNumber'] : '';
$uDFEmail = "my#email";
$uDFSubject = (isset($_POST['uDFSubject'])) ? $_POST['uDFSubject'] : '';
$uDFMessage = $uDFName . "\r\n" . $uDFNumber . "\r\n" . "just testing";
$message = wordwrap($message, 70, "\r\n");
mail($uDFEmail, $uDFSubject, $uDFMessage);

You have to open and send the request outside of the event handler function. The onreadystatechange handler only executes when the ready state of your request changes.
If you don't open and send the request, the handler function is not executed, and you won't see any results.
This solution should work:
var httpRequest = new XMLHttpRequest();
// this function executes whenever the ready state of the request changes
httpRequest.onreadystatechange = function () {
if (httpRequest.readyState === XMLHttpRequest.DONE && httpRequest.status === 200) {
var response = JSON.parse(httpRequest.responseText);
}
}
// open the request ...
httpRequest.open('POST', '../userData.mail.php')
httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
// ... and send it
httpRequest.send('uDFName=' + encodeURIComponent(data[0]) + 'uDFNumber=' + encodeURIComponent(data[1]) + 'uDFNumber=' + encodeURIComponent(data[3])
+ 'uDFNumber=' + encodeURIComponent(data[4]));

Run Javascript script from ajax response

I want to call a JS Script in Ajax response. What it does is pass the document.getElementById script to the Ajax responseText.
The current code returns me this error: Uncaught TypeError: Cannot set property 'innerHTML' of null
This is done with Visual Studio Cordova..
Ajax:
$("#loginBtn").click(function() {
var username = document.getElementById("username").value;
var password = document.getElementById("password").value;
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function () {
if (this.readyState == 4 && this.status == 200) {
document.write(this.responseText);
}
}
xmlhttp.open("POST", "http://www.sampleee.esy.es/login.php", true);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send("username=" + username + "&" + "password=" + password);
});
PHP:
if($count == 1){
echo "document.getElementById('alertBox').innerHTML = 'Login Success!';
document.getElementById('alertBox').className = 'alert alert-success';
document.getElementById('alertBox').style.display = 'block';
setTimeout(function () {
window.location.href = '../html/dashboard.html';
}, 1000);
";
}else{
echo "document.getElementById('alertBox').innerHTML = 'Invalid login details';
document.getElementById('alertBox').className = 'alert alert-danger';
document.getElementById('alertBox').style.display = 'block';
";
}

You can solve it by a small change, you just have to write JS code in the AJAX success that you wrote in your PHP page. In the PHP page, there is no alertBox element, that's why the error occurred.
Your JS code will be like this:
$("#loginBtn").click(function() {
var username = document.getElementById("username").value;
var password = document.getElementById("password").value;
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function () {
if (this.readyState == 4 && this.status == 200) {
if(this.responseText=="success"){
document.getElementById('alertBox').innerHTML = 'Login Success!';
document.getElementById('alertBox').className = 'alert alert-success';
document.getElementById('alertBox').style.display = 'block';
setTimeout(function () {
window.location.href = '../html/dashboard.html';
}, 1000);
}elseif(this.responseText=="error"){
document.getElementById('alertBox').innerHTML = 'Invalid login details';
document.getElementById('alertBox').className = 'alert alert-danger';
document.getElementById('alertBox').style.display = 'block'
}
}
}
xmlhttp.open("POST", "http://www.sampleee.esy.es/login.php", true);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send("username=" + username + "&" + "password=" + password);
});
And PHP code like:
if($count == 1){
echo "success";
}else{
echo "error";
}

Basically you get that error because the thing you're trying to change is not on the page when you look for it.
What you need to do is, do not write javascript with PHP. You return something like an int from php and then use that to decide what the javascript does.
You have the html on the page and just change the content inside it.
$("#loginBtn").click(function() {
var username = document.getElementById("username").value;
var password = document.getElementById("password").value;
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
var str = this.responseText; //you may need to trim whitespace
var alert = document.getElementById('alertBox');
if (str.trim() == 1) {
alert.innerHTML = 'Login Success!';
alert.className = 'alert alert-success';
alert.style.display = 'block';
setTimeout(function() {
window.location.href = '../html/dashboard.html';
}, 1000);
}
else {
alert.innerHTML = 'Invalid login details';
alert.className = 'alert alert-danger';
alert.style.display = 'block';
}
}
xmlhttp.open("POST", "http://www.sampleee.esy.es/login.php", true);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send("username=" + username + "&" + "password=" + password);
});
<div id="alertbox"></div>
PHP Code:
if($count == 1){
echo 1;
}
else{
echo 0;
}

Use eval like below
$("#loginBtn").click(function() {
var username = document.getElementById("username").value;
var password = document.getElementById("password").value;
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function () {
if (this.readyState == 4 && this.status == 200) {
var fun = eval(this.responseText);
}
}
xmlhttp.open("POST", "http://www.sampleee.esy.es/login.php", true);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send("username=" + username + "&" + "password=" + password);
});

Ajax, JS function returning undefined value [duplicate]

This question already has answers here:
How do I return the response from an asynchronous call?
(41 answers)
Closed 6 years ago.
I am very new to all of this, I am tying to learn Ajax as well as Javascript, I am getting the value from a php file, but when I try to return the value in the method I get a undefined value which i log in the console., I am after trying a lot of thing but with no success. Can some one please educate me on this. And please criticize me code im sure there is a lot of bad practice.
Thanks
function checkEmail(){
var xhttp;
var status;
xhttp = new XMLHttpRequest();
var email = document.getElementById('email2').value;
xhttp.onreadystatechange = function() {
if (xhttp.readyState == 4 && xhttp.status == 200) {
var xmlResponse = xhttp.responseText;
status = xmlResponse;
}
};
xhttp.open("GET", "php/ajaxCom.php?email="+email, true);
xhttp.send();
return status;
}
<?php
include 'base.php';
$status;
$email_in_use = $_GET['email'];
$query = mysqli_query($link, "SELECT * FROM users WHERE email='".$email_in_use."'");
if(mysqli_num_rows($query) > 0){
$status = "false";
}else{
$status = "true";
}
echo $status;
?>
This is where I call the checkEmail
function getStatus(field, name, value) {
var status = null;
if (!field.attr('required')) return null;
if (!value) status = 'Please fill out the required field: ' + name;
else if (emailField.test(name) || emailField.test(field.attr('type'))) {
var b = checkEmail();
console.log(b);
if (!emailValue.test(value)) {
status = 'Please enter a valid email address for: ' + name;
}else if ( b == "false"){
alert("im here");
status = 'Please enter a valid email this email already has an acount';
}
}
return status;
}
update
The stats alert is shown correctly but the console log is still showing undefined
function getStatus(field, name, value) {
var status = null;
if (!field.attr('required')) return null;
if (!value) status = 'Please fill out the required field: ' + name;
else if (emailField.test(name) || emailField.test(field.attr('type'))) {
var b;
checkEmail(function(status) {
alert('Status: ' + status);
b = status;
});
console.log(b);
if (!emailValue.test(value)) {
status = 'Please enter a valid email address for: ' + name;
}else if ( b == "false" || b == "true"){
alert("im here");
status = 'Please enter a valid email this email already has an acount';
}
}
return status;
}

You're returning status immediately, where as the actual AJAX calls returns asynchronously.
You need to change your flow so that checkEmail would accept a callback function as parameter instead of returning it. Something like that:
function checkEmail(callback) {
xhttp.onreadystatechange = function() {
if (xhttp.readyState == 4 && xhttp.status == 200) {
var xmlResponse = xhttp.responseText;
status = xmlResponse;
callback(status);
}
};
...
checkEmail(function(status) {
alert('Status: ' + status);
});