CODEWITHSUNDEEP
javascriptphparraysjson
user1906399
user1906399

Reputation: 771

Why do we need json or php's serialization method to access php array in JS , if we can achieve the same thing without them?

Usually we use json(as it is a better option than php's serialization) to transfer a php array into JS to access it from there, or we can use cookie. But can't we do the same thing without those? For example lets take a look at the first code.

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <?php
     $elements = array('myname', 'myage');
    ?>

    <script type="text/javascript">

    var elements = <?php echo json_encode($elements) ; ?> ;

  //use the elements array afterwards

    </script>

</body>
</html>

But we can access that php array without using json, like this way also

   <script type="text/javascript">

    var elements = [];
      <?php foreach($elements as $element) : ?> 

      elements.push("<?php echo $element; ?>");

      <?php endforeach; ?>

 //use the elements array afterwards

    </script>

So other than secutity reason why do we need json here?

Upvotes: 0

Views: 113

Answers (3)

PaulH
PaulH

Reputation: 3049

jsonencode() converts the php array into a string in json format. It is one php call handled locally by the server.

The foreach alternative mixes server and js execution to obtain a similar result. It is more complex to read and longer to execute, both for the server and the javascript client.

Javascript strings can be delimited by " or '. If they are delimited by " and the string contains ", that would signal an end of string, the remainder or the string would be handled as code, leading to a parsing error. Therefore, the " must be escaped like so \". json_encode() does that for you, echo doesn't.

So keep to the first.

Upvotes: 1

MinusFour
MinusFour

Reputation: 14423

Keep in mind that you are actually printing a lot of javascript push functions.

I guess the real advantages of JSON comes at the time when using AJAX calls. You'll have no help from PHP to parse the information straight into your javascript script block.

Upvotes: 1

Sam Dufel
Sam Dufel

Reputation: 17598

There are a number of special cases you would need to address when embedding php variables in javascript (which json_encode already handles for you).

For strings:

  • Any newline characters in a php string need to be escaped
  • Any quotation marks of the same type as the surrounding quotes will need to be escaped
  • The string must be quoted

For numbers:

  • The number should not be quoted - otherwise, the data type on the javascript end will change

For arrays:

  • Each element could be of a different type, so you'd need a recursive function to handle the encoding correctly. Also, PHP associative arrays map to json objects, while numeric arrays map to json arrays. This is somewhat awkward to handle in your own code.

** Not an exhaustive list, there are probably a few other cases.

It's very easy to make a mistake when writing your own encoding script, and it'll most likely run slower than the PHP json_encode function.

Upvotes: 2

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