Best method for converting a PHP array to javascript

Question

I am passing a PHP array to a javascript function. The only way I know to do this is to create a js array from the PHP array and pass that to the js function. But this creat

Answer 1

Use JSON. see why JSON over XML: http://thephpcode.blogspot.com/2008/08/why-json-over-xml-in-ajax.html

To use json in PHP simply:

<?php

  echo '<script type="text/javascript">/* <![CDATA[ */';
  echo 'var train = '.json_encode($array);
  echo '/* ]]> */</script>';

?>

the variable train in Javascript will be an object containing properties and arrays based on your PHP variable $array.

To parse or iterate through the train object, you can use for ... in statements for JSON arrays, and directly use object.property for JSON objects.

See this:

<?php

  $array = array(array('id'=>3,'title'=>'Great2'),array('id'=>5,'title'=>'Great'),array('id'=>1,'title'=>'Great3'))
  echo '<script type="text/javascript">/* <![CDATA[ */';
  echo 'var train = '.json_encode($array);
  echo '/* ]]> */</script>';

?>

The output will be:

 var train = [{id:3,title:'Great2'},{id:5,title:'Great'},{id:1,title:'Great3'}];

the variable train becomes an array of objects. [] squrare brackets are arrays, holding more arrays or objects. {} curly braces are objects, they have properties to them.

So to iterate the train variable:

<script type="text/javascript">

  var train = [{id:3,title:'Great2'},{id:5,title:'Great'},{id:1,title:'Great3'}];

  for(i in train){
    var t = train[i]; // get the current element of the Array
    alert(t.id); // gets the ID
    alert(t.title); // gets the title
  }

</script>

Simple! Hope that really helps.

Answer 2

json_encode. See http://us3.php.net/manual/en/function.json-encode.php

Answer 3

A more space-efficient way of encoding Javascript data structures is called JSON.

As of PHP 5.2.0, you can use the following function to spit out some JSON: json_encode().

Answer 4

You can always use XMLHttpRequest to load it as JSON or XML.