How to pass an array using PHP & Ajax to Javascript?

Apologies if this explanation isn't clear, it's hard for me to understand too. How can I use PHP & Ajax to send an array to Javascript? I'm using Ajax to get an array of photos, which I'm then looking to append to an empty <div> on my page.

The jQuery looks as follows:

$.ajax({
    url: "<?php echo site_url('demo/getPhotos/'); ?>",
    type: 'POST',
    data: form_data,
    success: function(data) {
        alert(data);
   }

And the PHP function getPhotos looks like this:

<?php

$photos = array();

foreach ($data as $photo) {
    array_push($photos,$photo['source']);
    }

// echo json_encode($photos); How should I be returning $photos?

If I simply echo $photos; the data is sent to the success callback, but it doesn't appear to be in a usable format.

If I do a var_dump($photos) in PHP, the result looks something like:

array(4) {
  [0]=>
  string(14) "some_image.jpg"
  [1]=>
  string(14) "some_image.jpg"
  [2]=>
  string(14) "some_image.jpg"
  [3]=>
  string(14) "some_image.jpg"
}

I've tried various combinations of json_encode and the like but really I am guessing and not sure of the theory behind it. What's the best way to pass data from PHP to Javascript in this context?

Answers:

Answer

Try:

$.ajax({
    url: "<?php echo site_url('demo/getPhotos/'); ?>",
    type: 'POST',
    data: form_data,
    dataType:"json",
    success: function(data) {
        alert(data[0]);
   }

On the PHP side, you'll be wanting to print:

print json_encode($photos);

Another thing you might try in order to better encapsulate your code, and as an example of further JSON gooodness, would be:

print json_encode(array("photolist"=>$photos,"photo_owner"=>"Me!"));

Then on the server, you'd access these with:

data.photolist[0]; //First photo
data.photo_owner;  //The owner of the photo set
Answer

I made an array $result in PHP and at the end of request.

 echo json_encode($result); 

and in JS $.post handler function :

var obj = $.parseJSON(data);
var v = data.k; 

where k is key value in associative array.

Answer

json_encode is definitely the way to go. jQuery even has built-in support for parsing JSON. You could use e.g.

$.ajax({
    url: "<?php echo site_url('demo/getPhotos/'); ?>",
    type: 'POST',
    data: form_data,
    dataType: 'json', // will automatically convert array to JavaScript
    success: function(array) {
        alert(array[0]); // alerts first string
    }
});
Answer

return the json itself and then construct the array in js by looping over the json as follows:

var array=[];
for(var key in json)
{    
    if(json.hasOwnProperty(key))
      array.push(json[key]);
}

Or you can simply work with the json itself any reason for needing the array?

something like json[0] or json[1] etc.

Answer

json_encode rulez when you need this stuff.

I recently learned this cool thing too! Here's how you do it:

function jsonResponse($array) {
     header('Content-type: application/json; charset=utf-8;');
     die(json_encode($array));
}

This is optional, if you want to do it, you don't have to, but in my MVC system, I tend to write this way... So first I make an ajax request (prototype), to a script, that later calls this function jsonResponse I mentioned earlier...

    new Ajax.Request('URL',
{
    method:'post',
    onSuccess: function(transport){
        res = transport.responseJSON;
        $('actionInformation').update(res.username);
    },
    onFailure: function(){
        alert('Something went wrong...')
    }
});

This is the jscript code, notice the res.msg, this is where we can operate with array. But, be sure to send response in JSON format in your PHP, using the jsonResponse function, it's easy to use, e.g., your php function can look something like this :

function ajax_get_user() {
     $userName = 'Adrian';
     $active = 1;
     jsonResponse(array('username' => $username, 'active' = $active));
}

Later you can get it easy, res.username, res.active.

I think this should do it!

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