Develop Reference

Cannot read property toLowerCase of undefined

So, I am working on an audio part where I fetch my words from a JSON file and when I show them on my front-end it should onclick on the audio button fetch the word from the server and create the audio... But I keep on getting Cannot read property toLowerCase of undefined and I cannot seem to find the error.
let's start with the variables I declared:
var MEDIAARRAY;
var WORDS;
var audioArray;
var audio = new Audio();
var LANGUAGE;
var SOUNDARRAY;
The piece of code (I took over the code given as answer and it helped me a bit further so I decided to edit the question with the code I have right now).
$(document).ready(function () {
getFileArray();
});
$(document).on("click", ".sound", function () {
getFileArray("SomeLanguage");
var foundID = MEDIAARRAY.audio.lowercase.indexOf($(this).parent().find('.exerciseWord').val().toLowerCase() + '.mp3');
var currentVal = $(this).parent().find('.fa-volume-up');
if (foundID > -1) {
var audio = new Audio();
audio.src = 'TheServerURL' + MEDIAARRAY.audio.path + MEDIAARRAY.audio.files[foundID] + '';
audio.play();
}
});
The line where the error occurs:
var foundID = MEDIAARRAY.audio.lowercase.indexOf($(this).parent().find('.exerciseWord').val().toLowerCase() + '.mp3');
The button where the class sound is appended to:
function getAudioForWords() {
var audioBtn = $('<a/>', {
'class': 'sound btn btn-primary'
}).html('<i class="fa fa-volume-up"></i>');
return audioBtn;
}
the code where class exerciseWord gets append to:
var wordCol = $('<div>', {
class: 'col-md-9 ExerciseWordFontSize exerciseWord',
'id': 'wordInput[' + ID123 + ']',
text: exercise.word
});
and the piece of code that gets the fileArray, but most likely will be useless for you to inspect, but it was related to my code so... yeah.
function getFileArray(param)
{
var request = {
language: param
};
$.ajax(
{
url: "TheServerURL",
type: "POST",
async: true,
data: request,
dataType: 'json',
}).done(function (response)
{
console.log(response)
MEDIAARRAY = response;
audioArray = response.audio;
console.log(audioArray);
});
}

The error states varialble MEDIAARRAY remains uninitialized somewhere in your code flow. See if following takes you close to the resolution
You have not mentioned at what point getFileArray function is called. Call to getFileArray function is critical because that is when MEDIAARRAY is assigned value.
Ensure getFileArray is called before you access any propery of MEDIAARRAY.
Ensure your API always returns object which contains audio property.
Example,
$(document).on("click", ".sound", function () {
//Ensure you supply parameter value to your function(i.e. value of the element you take user input from)
getFileArray("SomeLanguage");
var foundID = MEDIAARRAY.audio.lowercase.indexOf($(this).parent().find('.exerciseWord').val().toLowerCase() + '.mp3');
var currentVal = $(this).parent().find('.fa-volume-up');
if (foundID > -1) {
var audio = new Audio();
audio.src = 'TheServerURL' + MEDIAARRAY.audio.path + MEDIAARRAY.audio.files[foundID] + '';
audio.play();
}
});

Avoid identical client ajax request on refresh

I would like to test if the ajax request is identical so it can be aborted or some other alert action taken?
In reality clients can change the request via a few form elements then hit the refresh button.
I have made a poor attempt at catching the identical request. Need to keep the timer refresh functionality.
<script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"></script>
<script type="text/javascript">
var current_request_id = 0;
var currentRequest = null;
var lastSuccessfulRequest = null;
function refreshTable() {
$('#select').html('Loading');
window.clearTimeout(timer);
//MY CATCH FOR DUPLICATE REQUEST NEEDS WORK
if (lastSuccessfulRequest == currentRequest)
{
//currentRequest.abort();
alert('Duplicate query submitted. Please update query before resubmission.');
}
var data = {
"hide_blanks": $("#hide_blanks").prop('checked'),
"hide_disabled": $("#hide_disabled").prop('checked'),
};
json_data = JSON.stringify(data);
current_request_id++;
currentRequest = $.ajax({
url: "/calendar_table",
method: "POST",
data: {'data': json_data},
request_id: current_request_id,
beforeSend : function(){
if(currentRequest != null) {
currentRequest.abort();
}
},
success: function(response) {
if (this.request_id == current_request_id) {
$("#job_table").html(response);
$("#error_panel").hide();
setFixedTableHeader();
}
},
error: function(xhr) {
if (this.request_id == current_request_id) {
$("#error_panel").show().html("Error " + xhr.status + ": " + xhr.statusText + "<br/>" + xhr.responseText.replace(/(?:\r\n|\r|\n)/g, "<br/>"));
}
},
complete: function(response) {
if (this.request_id == current_request_id) {
$("#select").html("Refresh");
window.clearTimeout(timer);
stopRefreshTable();
window.refreshTableTimer = window.setTimeout(refreshTable, 10000);
lastSuccessfulRequest = currentRequest;
}
}
});
}
//TIMER STUFF TO refreshTable()
//THIS SECTION WORKS FINE
var startDate = new Date();
var endDate = new Date();
var timer = new Date();
function startRefreshTable() {
if(!window.refreshTableTimer) {
window.refreshTableTimer = window.setTimeout(refreshTable, 0);
}
}
function stopRefreshTable() {
if(window.refreshTableTimer) {
self.clearTimeout(window.refreshTableTimer);
}
window.refreshTableTimer = null;
}
function resetActive(){
clearTimeout(activityTimeout);
activityTimeout = setTimeout(inActive, 300000);
startRefreshTable();
}
function inActive(){
stopRefreshTable();
}
var activityTimeout = setTimeout(inActive, 300000);
$(document).bind('mousemove click keypress', function(){resetActive()});
</script>
<input type="checkbox" name="hide_disabled" id="hide_disabled" onchange="refreshTable()">Hide disabled task<br>
<br><br>
<button id="select" type="button" onclick="refreshTable();">Refresh</button>

I'd use the power of .ajaxSend and .ajaxSuccess global handlers.
We'll use ajaxSuccess to store a cache and ajaxSend will try to read it first, if it succeeds it will trigger the success handler of the request immediately, and abort the request that is about to be done. Else it will let it be...
var ajax_cache = {};
function cache_key(settings){
//Produce a unique key from settings object;
return settings.url+'///'+JSON.encode(settings.data);
}
$(document).ajaxSuccess(function(event,xhr,settings,data){
ajax_cache[cache_key(settings)] = {data:data};
// Store other useful properties like current timestamp to be able to prune old cache maybe?
});
$(document.ajaxSend(function(event,xhr,settings){
if(ajax_cache[cache_key(settings)]){
//Add checks for cache age maybe?
//Add check for nocache setting to be able to override it?
xhr.abort();
settings.success(ajax_cache[cache_key(settings)].data);
}
});
What I've demonstrated here is a very naïve but functional approach to your problem. This has the benefit to make this work for every ajax calls you may have, without having to change them. You'd need to build up on this to consider failures, and to make sure that the abortion of the request from a cache hit is not getting dispatched to abort handlers.

One valid option here is to JSON.Stringify() the objects and compare the strings. If the objects are identical the resulting serialised strings should be identical.
There may be edge cases causing slight differences if you use an already JSONified string directly from the response so you'll have to double check by testing.
Additionally, if you're trying to figure out how to persist it across page loads use localStorage.setItem("lastSuccessfulRequest", lastSuccessfulRequest) and localStorage.getItem("lastSuccessfulRequest"). (If not, let me know and I'll remove this.)

Return value from a function returns undefined

I have an html which has a form that a user could enter url if the value of the input text has www. in it i will create a variable and return it to the function then pass it to the ajax but it seems that when I check it(ajaxData var) in the console it says undefined.
<form action="" id="defaultForm">
<input type="text" id="url">
<button id="submit">Submit</button>
</form>
JS:
$(function () {
function myreturnValue() {
$('#defaultForm').submit(function () {
var w = 'www.';
var current = $('#url').val();
var appendW = w + current;
if (current.match('www.')) {
console.log('it already consists of www');
var returnValue = 'site_url:' + current; //site_url:www.domain.com or http://
console.log(typeof returnValue);
return returnValue;
} else {
var returnValue = 'site_url:' + appendW; //www+url
console.log(current);
console.log(appendW);
console.log(returnValue);
return returnValue;
}
}); //end submit
}
var ajaxData = myreturnValue();
console.log(typeof ajaxData);
var data = 'data:{' + ajaxData + '}';
});
then in the ajax I will pass the data variable. I hope my explanation is kinda clear.

Currently in your code, myreturnValue function only execute a code to register an event listener to your form, without return value (your return statement will only be triggered on submit event), so that's why it will return undefined at the first time.
Try this:
Put your url detect logic in myreturnValue function
Then put a code to prevent default submit event to be fired
Finally register a event listener for submit button.
And your original regex www. means match www with one other character, like wwww. and www0. will be valid. You may consider changing it to other regex like this one
$(function() {
function myreturnValue() {
var w = 'www.';
var current = $('#url').val();
var appendW = w + current;
if (current.match(w)) {
console.log('it already consists of www');
var returnValue = 'site_url:' + current; //site_url:www.domain.com or http://
console.log(typeof returnValue);
return returnValue;
} else {
var returnValue = 'site_url:' + appendW; //www+url
console.log(current);
console.log(appendW);
console.log(returnValue);
return returnValue;
}
}
$('#defaultForm').submit(function(e) {
e.preventDefault();
});
$('#submit').on('click', function() {
var data = 'data:{' + myreturnValue() + '}';
console.log(data);
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form action="" id="defaultForm">
<input type="text" id="url">
<button id="submit">Submit</button>
</form>

A few problems here.
Calling $('#defaultForm').submit(function () { binds a submit handler to the form. It does not submit the form nor execute the function. Please familiarize yourself with the documentation.
Your myreturnValue() doesn't return anything. You only have one top level line which is the above submit binding. Not only is it not executed, but return inside that function does not propagate up like you're expecting it to. Returning inside an event handler won't do anything in any context.
Don't declare vars inside if branches in general.
Here's a quick attempt to reorganize this code, but with this many problems the corrected code may depend on your specific needs.
(function () {
$('#defaultForm').submit(function (event) {
// prevent default form submit
event.preventDefault();
var w = 'www.';
var current = $('#url').val();
var appendW = w + current;
var value;
if (current.match('www.')) {
console.log('it already consists of www');
value = 'site_url:' + current; //site_url:www.domain.com or http://
console.log(typeof returnValue);
} else {
value = 'site_url:' + appendW; //www+url
console.log(current);
console.log(appendW);
console.log(returnValue);
}
var data = 'data:{' + ajaxData + '}';
// Do whatever you want with data here
});
// If you want to now submit the form by hand...
$('#defaultForm').submit();
});

In your code, the myreturnValue() is only return the returnValue of the function in Submit. 'myreturnValue' function return anything because it doesn't any return value.
You executed unnecessary function to get the ajaxData.
To get the ajaxData, You only need to
$('#defaultForm').submit(function () {
contents
}
If fix the code simple...
$('#defaultForm').submit(function () {
var returnValue;
var w = 'www.';
var current = $('#url').val();
var appendW = w + current;
if (current.match('www.')) {
console.log('it already consists of www');
returnValue = 'site_url:' + current; //site_url:www.domain.com or http://
console.log(typeof returnValue);
} else {
returnValue = 'site_url:' + appendW; //www+url
console.log(current);
console.log(appendW);
console.log(returnValue);
}
console.log(typeof returnValue);
var data = 'data:{' + ajaxData + '}';
console.log('data : ', data)
});
Please, Note : http://codepen.io/onyoon7/pen/mRdJJV

AJAX - reload page if JSON has changed

I cannot find a suitable way to achieve this:
I have this script
<script type="text/javascript">
function updateSpots() {
$.ajax({
url : '/epark/api/spots/last',
dataType : 'text',
success : function(data) {
var json = $.parseJSON(data);
var currentMessage = json.dateTime;
var idPosto = json.idPosto;
console.log('current '+currentMessage);
console.log('old '+oldMessage);
if(currentMessage != oldMessage){
setTimeout(function(){location.reload();}, 5000);
$('#idPosto').toggle("higlight");
}
oldMessage = currentMessage;
}
});
}
var intervalId = 0;
intervalId = setInterval(updateSpots, 3000);
var oldMessage ="";
</script>
This should check every 3 seconds if the dateTimehas changed on the JSON.
The problem is that I cannot get to go further first step. I mean, when the page loads, oldMessageempty so the if condition is not satisfied. If I could "jump" this first iteration, then everything would go well...

var oldMessage = false;
//...
if (oldMessage && oldMessage !== currentMessage) {
//...

Getting data from MySql table with no refresh

I have a code that counts down and when the countdown reaches 0 I want it to grab data from a MySql table and present it on the page without reloading.
I know my countdown works, but it is when I add the code to get the data from the PHP page it stops working. I know my PHP page works and grabs the correct data and presents it.
Here is the code I am currently using.
Any ideas?
<div id="countmesg"></div>
<div id="checking"></div>
<div id="name-data"></div>
<script src="jquery.js" type="text/javascript"></script>
<script type="text/javascript">
$(document).ready(function () {
var delay = 10;
function countdown() {
setTimeout(countdown, 1000);
$('#countmesg').html("Auction ends in " + delay + " seconds.");
delay--;
if (delay < 0) {
$('#countmesg').html("Auction ended.");
delay = 0;
}
}
countdown();
});
</script>
<script type="text/javascript">
$(document).ready(function () {
var delay = 2;
function countdown() {
setTimeout(countdown, 100);
$('#checking').html("Checking in " + delay + " seconds.");
delay--;
if (delay < 0) {
$('#checking').html("Checking again....");
var name = 'tom';
$.post('cdown.php', {
name: name
}, function (data) {
$('div#name-data').text(data);
};
delay = 2;
}
}
countdown();
});
</script>
The 3 lines that are supposed to be grabbing the PHP file are:
var name = 'tom';
$.post('cdown.php', {name: name}, function(data) {
$('div#name-data').text(data);
PHP Code:
<?php
require 'connect.php';
$name = 'tom';
$query = mysql_query("
SELECT `users`.`age`
FROM `users`
WHERE `users`.`name` = '" . mysql_real_escape_string(trim($name)) . "'"
);
echo (mysql_num_rows($query) !== 0) ? mysql_result($query, 0, 'age') : 'Name not found';
?>

use $.ajax instead of $.post
$.ajax(//url to php//).done(
function (data) { //data is from the php
//do stuff
}
)

Code you provided (3 lines):
var name = 'tom';
$.post('cdown.php', {name: name}, function(data) {
$('div#name-data').text(data);
It seems like you have an incomplete $.post(...) statement. If you check your Console you should see some Exceptions. What are they?
Update your 3 lines to this:
var name = 'tom';
$.post('cdown.php', {name: name}, function(data) {
$('div#name-data').html(data);
});