Question

I have a two dimensional array in php that I need to express as a javascript variable or object. I’ve looked into json encoding it and decoding it for use as a javascript object and this doesn’t make sense since I want to loop through my javascript convert. Expressing the php array as a javascript two dimensional array also doesn’t really make sense because of how complicated multidimensional arrays are in javascript. What is the standard way of doing something like this? As I said, I need to be able to loop through the results. The PHP array holds a number in the first dimension and a page name in the second. I’m trying to find an efficient way to assign ids to a check box associated with each page name. I want to be able to loop through a javascript variable and check each id if the check box has been checked or not. Thanks for your help, I’m not sure how to proceed.

Answer 1

JSON is the perfect way to do this. Javascript Object Notation is simply Javascript syntax to express arbitrary values, objects or otherwise. They’re perfect for transferring PHP values to Javascript:

<?php $arr = array('foo', 'bar', 'baz', 42); ?>
<script type="text/javascript">
    var arr = <?php echo json_encode($arr); ?>;
</script>

This is equivalent to you typing:

<script type="text/javascript">
    var arr = ["foo", "bar", "baz", 42];
</script>

json_encode gives you a perfect Javascript array which you can loop through or do anything with you’d usually do with a Javascript array. You just need to build the array/object/value you need.

What you may need to take care of is that continuously numerically indexed arrays result in JSON arrays, but anything else results in a JSON object. E.g.:

array('foo', 'bar')              -> ["foo", "bar"]
array(0 => 'foo', 1 => 'bar')    -> ["foo", "bar"]
array(1 => 'foo', 0 => 'bar')    -> { "1" : "foo", "0" : "bar" }