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I'm having trouble accessing an array created in php, to use in a javascript block. I know about

<?php echo json_encode($myArray); ?>

but I'm not getting any results out of it.

I have a 'index.html' file where I try to access the array through javascript. The html page exists out of a drop down menu. When the user chooses an item in that drop down menu, the chosen item is used as an argument to retrieve data from a database.

The 'ajax.js' file contains the code to execute the 'retrieve.php' file which constructs the array ('$myArray') from database content. So the array is retrieved through an ajax call.

Can I 'echo' to the javascript code from my php file:

echo 'dataArray = ' . json_encode($data_array) . ';';

and use that javascript variable? In other words, how can I execute my javascript code using that new 'dataArray' variable?

To get the bigger picture: I'm trying to use that array for use in a 'Google Chart', for which I need to use javascript to display the chart. I can query all data and put it in a php array, but I'm not succeeding in transfering it properly to my html page with javascript and reload the chart.

Edit: I use an ajax call to no to reload the entire page.

share|improve this question
    
Are you trying to get the JSON back as a response from an AJAX call? –  Mathletics Apr 16 '12 at 13:37
    
First of all, you can't access whatever php variable in javascript. –  Your Common Sense Apr 16 '12 at 13:37
    
@Mathletics: Yes, I am. –  user729103 Apr 16 '12 at 13:47

3 Answers 3

up vote 2 down vote accepted

Instead of " echo 'dataArray = ' . json_encode($data_array) . ';'; ", you should just write this- "echo json_encode($data_array)"
And then interpret it in the client using JSON.parse(response) where response the response you received from the server (the json)

share|improve this answer
    
Thanks! I managed to get it to work, by using JSON.parse in my xmlhttp.onreadystatechange function and provide the JSON data to draw an updated chart. I'm not sure if this is the best way or if I should choose to use jQuery instead. –  user729103 Apr 17 '12 at 6:28
up vote 1 down vote

I found that the best way to do this is like so:

Client code:

<script>
    var phpdata = <?=json_encode($jsData)?>;
</script>

Server code:

$jsData = '';
$jsData->first = $first;
$jsData->second = $second_array;

Client side usage:

alert(phpdata.second[1]);

EDIT:

To get an array from php using AJAX, use jQuery http://api.jquery.com/jQuery.getJSON/

Client side:

var stored_array;
$.getJSON(url, function(data){
    stored_array = data;
    // run any other code you wish to run after getting the array.
});

Server side:

print(json_encode($array));

this will get a json encoded variable and store it for your use.

share|improve this answer
    
Will the php be able to output correctly if the '$jsData' variable is constructed during an AJAX call? –  user729103 Apr 16 '12 at 13:49
    
Not exactly sure how you're planning to do that. are you making an ajax call to get the array, and then run? or do you have the array when you render the page in the first place? –  Rodik Apr 16 '12 at 13:53
    
Initially the user has to select something (here: from a drop down), then I'm making an ajax call to get the array, and then I will draw the chart. When the user selects another item from the drop down, I want to update the chart. –  user729103 Apr 16 '12 at 14:02
    
I edited my answer. check it out –  Rodik Apr 16 '12 at 14:19
    
Thanks, I'll check out the jQuery alternative to see if it's a better solution than parsing the response in my xmlhttp.onreadystatechange method. –  user729103 Apr 17 '12 at 6:29
up vote 0 down vote

Yes you can use this array of php by assigning the above json_encode function

You can use it as associative array if the array is associative or object used in php and if no-associative you can use it as normal array.

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