Unusual behavior of php implode in javascript

Question

I have been using PHP to get value from the database and storing them in an array and when I echo the code using implode in PHP, it is working absolutely fine(For single as well as multiple values in the data arrays.

PHP Code for Reference

$data_Sad= array();
$data_Like = array();

$data_Sad[] = 3;
//$data_Sad[] = 3;
$data_Like[] = 3;
//$data_Like[] = 3;

Now,

I want to assign that value to the javascript array. All i do is -

<script>    
js_array = new Array(<?php echo implode(',', $data_Sad);?>);
js_array1  = new Array(<?php echo implode(',', $data_Like); ?>);

alert(js_array);
alert(js_array1);
</script>

Now when I alert the js_array when it has single value then it simply returns/alerts an empty array string. While when I populate 2 or more values then it works perfectly fine.

Also, if I use json_encode then it works fine but again it is a string format output and all I need is int/number values.

Can anyone help me out solving the issue using implode of PHP or any other work around?

Thanks in anticipation :)

Have you tried using quotes?

Bernhard
– Bernhard

2017-09-25 04:56:53 +00:00
Commented Sep 25, 2017 at 4:56 — Bernhard
– Bernhard, Commented Sep 25, 2017 at 4:56

nithinTa · Accepted Answer · 2017-09-25 04:58:28Z

1

When you construct with single integer element to array it create a array of that size, instead of creating array with that element !

Create a single value array in JavaScript

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array#Parameters

answered Sep 25, 2017 at 4:58

nithinTa

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Comments

Mark · Accepted Answer · 2017-09-25 05:01:19Z

0

You should change your approach to use json_encode in php. It will ensure that the arrays are properly converted to usable JavaScript objects and can work on more complex arrays including associative array.

You can also use php short tags when simply echoing data to a template. e.g.

$data_Sad= array();
$data_Like = array();

$data_Sad[] = 3;
$data_Like[] = 3;

Now,

I want to assign that value to the javascript array. All i do is -

<script>    
js_array = <?=json_encode($data_Sad)?>;
js_array1 = <?=json_encode($data_Like)?>;

alert(JSON.stringify(js_array));
alert(JSON.stringify(js_array1));
</script>

answered Sep 25, 2017 at 5:01

Mark

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Comments

Naga · Accepted Answer · 2017-09-25 05:00:39Z

Try run the below code and you will understand the problem.

<?php

$data_Sad= array();
$data_Like = array();

$data_Sad[] = 3;
$data_Sad[] = 4;
//$data_Sad[] = 3;
$data_Like[] = 3;
$data_Like[] = 5;
//$data_Like[] = 3;
echo "<pre>";print_r($data_Sad);print_r($data_Like);echo "</pre>";
?>
<script>    
js_array = new Array(<?php echo implode(',', $data_Sad);?>);
js_array1  = new Array(<?php echo implode(',', $data_Like); ?>);

alert(js_array);
alert(js_array1);
</script>

When PHP array has one numeric value, it will taking as array initialization.

To avoid such issues, use the below code.

<?php

$data_Sad= array();
$data_Like = array();

$data_Sad[] = 3;    
//$data_Sad[] = 3;
$data_Like[] = 3;    
//$data_Like[] = 3;
echo "<pre>";print_r($data_Sad);print_r($data_Like);echo "</pre>";
?>
<script>    
js_array = new Array(<?php echo '\''.implode('\',\'', $data_Sad).'\'';?>);
js_array1  = new Array(<?php echo '\''.implode('\',\'', $data_Like).'\''; ?>);

alert(js_array);
alert(js_array1);
</script>

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Unusual behavior of php implode in javascript

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Can anyone help me out solving the issue using implode of PHP or any other work around?

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Can anyone help me out solving the issue using implode of PHP or any other work around?

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