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Passing Array From PHP to JQuery json_encode

I have an HTML form generated by php which has a dropdown of voucherproviders.
I want to select the provider and have this populate the form for editing.
Here is my JQuery code:
$(document).ready(function() {
$(document).on('change','#id_voucherprovider',function(){
var voucher_providers = <?php echo json_encode($voucher_providers); ?>;
//The value I have got from the drop down is....
var value = $('#id_voucherprovider option:selected').val();
var vendortext = $('#id_voucherprovider option:selected').text();
//so the voucher provider is
alert(vendortext);
$('.ftext input').val(vendortext);
$("textarea#id_vendornotes").val(voucher_providers[value]);
});
});
voucherproviders is not being passed into the JQuery despite the echo json_encode($voucher_providers); code working when inline with the php code.
It seems to return a null array. Can anyone see what is wrong?
Many Thanks
Dave

var voucher_providers = <?php echo json_encode($voucher_providers); ?>;
json_encode returns a string, unless it is parsed it will not be usable. Use JQuery .parseJSON and you should have better results. :)
var jsonString = <?php echo json_encode($voucher_providers); ?>;
var voucher_providers = $.parseJSON(jsonString);

try this (note the quotes):
var voucher_providers = JSON.parse('<?php echo json_encode($voucher_providers); ?>');

parse your json ex: obj = JSON.parse(data);

Hi please check the json format at below site:-
http://jsonlint.com/
and check if this is fine.

Problems in passing PHP array to JavaScript

I understand that the format for passing a PHP array to Javascript is:
<script type="text/javascript">
var obj = <?php echo json_encode($php_variable); ?>;
</script>
I have a php function that stores some values in a longitude and latitude array. These array do hold the right values within php since print_r() within php shows me that the array is correct.
print_r($latitude_array);
print_r($longitude_array);
Now, I pass on this array to JS in this manner:
<script>
var lati_array = "<?php echo json_encode($latitude_array); ?>";
var longi_array = "<?php echo json_encode($longitude_array); ?>";
alert(lati_array[0]);
</script>
In the beginning, when I open the HTML file, it shows me an empty array (which is expected because the PHP arrays aren't filled yet). Then user enters something, the php arrays are filled up with longitudes and latitudes. These values should now be passed to JS. However, it doesn't alert anything after that. I can't be sure if array is successfully passed to JS. What am I missing?

Try this:
<script>
var data = <?php echo json_encode( $data ); ?>;
</script>

Try like below:
<?php
$array_var = array(111, 222, 333, 444);
?>
<script>
var array_var = "<?php echo json_encode($array_var); ?>";
console.log(array_var);
array_var = JSON.parse(array_var);
console.log(array_var);
alert(array_var[0]);
</script>

You are getting a string in lati_array , Try to convert it into json like this:
<script>
var lati_array = "<?php echo !empty($latitude_array) ? json_encode($latitude_array) : ''; ?>";
var longi_array = "<?php echo !empty($longitude_array) ? json_encode($longitude_array) : ''; ?>";
lati_array = JSON.parse(lati_array);
alert(lati_array[0]);
</script>

convert JS var to PHP and vice versa

Here I am getting values from textarea in array variable.
After that I convert javascript variable to PHP variable and perform some processing over it.
After process completed again I convert PHP to JS and alert. But when I alert, it gives empty result.
<script>
$( "#convert" ).click(function() {
var arabic = document.getElementById("ar").value; // ar is id of text area
<?php $ar_terms = "<script>document.write(arabic)</script>"?>
<?php
$string=implode(",",$ar_terms);
$result = array();
foreach ($ar_terms as $term) {
// echo $Arabic->ar2en($term);
array_push($result, $Arabic->ar2en($term));
}
$result=implode(",",$result);
?>
var arabic = new Array();
arabic='<?php echo $result; ?>';
alert(arabic);
});
</script>
Entire code is here : https://gist.github.com/karimkhanp/d4ac41fa864fd8ae0521

You can do one thing in this scenario to pass the variable from PHP to js. You can convert the array using json_encode() before echoing:
$result=json_encode( implode(",",$result) );
As a result, when you assign this variable to js in the <?= ?> block, it will read the json string and thus the array will be assigned:
arabic='<?php echo $result; ?>';

How to Pass a PHP array to JavaScript function?

First of all, this question looks a duplicate of Pass a PHP array to a JavaScript function, but I actually used the first solution of Pass a PHP array to a JavaScript function - and it doesnt seem to work:
More specifically, the php echo line in the code below seems to create erroneous js output according to console error message( Uncaught SyntaxError: Unexpected token <); the console shows created html starting with "var s1 = <br />
<font size='1'><table class='xdebug-error xe-notice' dir='ltr' border='1'..."
...while I'd expect a clean var s1 = [1,2,3,4,5,6,7,8,9] - the result I also see when I tested the echo line in ideone.com
Any idea why the echo line is creating this stuff, and how to fix this?
Related joomla php code:
<?php
// No direct access to this file
defined('_JEXEC') or die('Restricted access');
$document = JFactory::getDocument();
//add jqplot libraries
JHtml::_('jquery.framework');
JHTML::script(JUri::root() .'media/system/js/jquery.jqplot.min.js');
//$document->addStyleSheet(JUri::root() .'media/system/js/jquery.jqplot.min.css');
JHtml::stylesheet( JUri::root() . 'media/system/js/jquery.jqplot.min.css' );
JHTML::script(JUri::root() .'media/system/js/jquery.jqplot.min.css');
JHTML::script(JUri::root() .'media/system/js/jqplot.barRenderer.min.js');
JHTML::script(JUri::root() .'media/system/js/jqplot.categoryAxisRenderer.min.js');
JHTML::script(JUri::root() .'media/system/js/jqplot.pointLabels.min.js');
JHTML::script(JUri::root() .'media/system/js/jqplot.enhancedLegendRenderer.js');
JHTML::script(JUri::root() .'media/system/js/weqlib.js');
$chartvals = array(1,2,3,4,5,6,7,8,9);
?>
<head>
<script type="text/javascript">
jQuery(document).ready(function(){
var s1 = <?php echo json_encode(chartvals); ?>; //!the echo seems to create erroneous js output accoding to console(?)
plot1 = jQuery.jqplot ('chart1', [s1]); //copied from example at
}); //$(document).ready
</script>
</head>

You forgot the $ to referrence the chartvals var at the json_encode() function call:
var s1 = <?php echo json_encode(chartvals); ?>;
Should be
var s1 = <?php echo json_encode($chartvals); ?>;
To not trap into this sort of mistakes again you can add error_reporting(E_ALL); to the beginning of your script and set display_errors to on in your PHP config during development.

var s1 = <?php echo json_encode($chartvals); ?>; //!the echo seems to create

Sending PHP array to Javascript

I have created an array in PHP. And I need to get that array into a javascript function. This is what I have tried.
$sql = "SELECT * FROM Questions WHERE Form_ID='$FormID' AND QuestionsDataHave='YES' ORDER BY Questions_ID+0, Questions_ID";
$GetTheValidationRule = mysqli_query($con, $sql);
$ValidatinArray = array();
$J = 0;
while($RowVal = mysqli_fetch_array($GetTheValidationRule)){
$ValidatinArray[$J] = $RowVal['Validation_Type'];
$J++;
}
And This is my javascript code.
$(document).ready(function() {
$("form").submit(function(){
var P= <?php echo json_encode($ValidatinArray); ?>;
var O = P.length;
alert(O);
return false;
});
});
But this gives me an error like this
SyntaxError: syntax error
var P= <br />
Isn't it possible to get the array in this way. Please someone help me.
UPDATE: This is the final out put of my error message
<script>
$(document).ready(function() {
$("form").submit(function(){
alert('AAAAAAAAAAAAAAAAAAA');
var IDsOfTheColumns = document.getElementsByName("DataColumnID[]");
var Data = document.getElementsByName("DataInputValue[]");
var A = IDsOfTheColumns.length;
alert(A);
<br />
<b>Notice</b>: Undefined variable: ValidatinArray in <b>C:\xampp\htdocs\PHIS\CreateTheForm.php</b> on line <b>16</b><br />
var P = null; return false;
});
});
</script>

Sorry for the late response...Try rewriting your document.ready as:
$(document).ready(function() {
$("form").submit(function(){
var P = JSON.parse('<?php echo json_encode($ValidatinArray); ?>');
var O = P.length;
alert(O);
return false;
});
});

The problem is, that in the variable $ValidatinArray is not available in the file, that prints the javascript code. Maybe this manual page helps you:
http://www.php.net/manual/en/language.variables.scope.php

Try this:
<?php
echo ' <script>
$(document).ready(function() {
$("form").submit(function(){
var P= '. json_encode($ValidatinArray) . ';
var O=P.length;
alert(O);
return false;
});
});
</script>';
?>
What you do is simply echo the js using php.

Your tag is coming from the form that you are submitting. check what your form data is before you encode it to verify the output. you can use console.log($("form));
Also using form is not a good idea since if you have more than one form and form is a global name. For forms you should give it a unique form name like "myForm" so that you can target that specific form.
Hope this helps

first of all I recommend that you verify that the variable $ValidatinArray exists and that it is being passed correctly to the file where you are doing the "echo".
the error you show indicates that from the beginning the variable that contains the array does not exist.
if the SQL query is inside a php function check that you are returning the variable.
example
<?php
function GetData(){
// ... here is the code to get the information from the database ...
return $ValidatinArray;
}
$ValidatinArray = GetData();
?>
once you have validated that this array exists we can now see the problem of passing the data to JavaScript:
It all depends on how the structure is, if you have the PHP code and the JavaScript function in the same file you can simply use this method inside the php fil:
// ... php file code
?>
<script>
$(document).ready(function() {
$("form").submit(function(){
// you can use any of the two methods that I leave you here
// Using only json_enconde
var P= <?= json_encode($ValidatinArray) ?>;
// Using json_enconde to pass the array as a string and using JSON.parse to have JavaScript convert it to an object
var P= JSON.parse('<?= json_encode($ValidatinArray) ?>');
var O = P.length;
alert(O);
return false;
});
});
</script>
In case the php file is executed at the moment of opening the page and the file that contains your function in JavaScript is in another file:
You can generate a "global" JavaScript variable from the php code as follows
// ... code php file
?>
<script>
window.variablename = <?= json_encode($ValidatinArray) ?>
</script>
<?php
inside your JS file you can receive the array like this
$(document).ready(function() {
$("form").submit(function(){
var P= window.variablename ;
var O = P.length;
alert(O);
return false;
});
});
PD: using <?= is equivalent to using echo

In php json_encode the array like this:
$inlinejs='';
$inlinejs.='var validatinArray=\''.addslashes(json_encode($ValidatinArray)).'\';'."\n";
$inlinejs.='var validatinArray=eval(\'(\' + validatinArray + \')\');'."\n";
and in javascript:
$(document).ready(function() {
$("form").submit(function(){
<?php echo $inlinejs; ?>
console.log(validatinArray);
});
});