Retrieve php array from ajax

Question

I am trying to retrieve array that was created by php and send back to my JS script via ajax.

I am not sure how to display the value.

server side php

 $r=array();
 $r[] = 'aaa';
 $r[] = 'bbb';
 $r[] = 'ccc';


echo json_encode($r);

my JS

....ajax codes....

var p=document.getElementById('text');

if (xmlhttp.readyState==4 && xmlhttp.status==200){

    var r=xmlhttp.responseText;

   for (var i=0; i<r.length; i++){
        p.innerHTML= r[i] + '<br>';
   }

}

The output will be

a
a
a
b
b
b
c
c
c
//but I want these
aaa
bbb
bbb

I want to use javascript instead of $.ajax to complete this. Any ideas?? Thanks a lot.

Without ajax how could you get the result from server using javascript ? May be I didn't get your question. — The Alpha
– The Alpha, Commented Jul 6, 2012 at 6:58
I didn't post the entire codes, but I did send ajax to the server, create my php array and send back to my JS. My problem is having strange output. — FlyingCat
– FlyingCat, Commented Jul 6, 2012 at 7:00
You should JSON.parse() the response you get in xmlhttp.responseText, it will not magically decode JSON by itself as jQuery does. — lanzz
– lanzz, Commented Jul 6, 2012 at 7:03

starbeamrainbowlabs · Accepted Answer · 2012-07-06 07:07:43Z

3

The easiest way to transfer an array from the server to the client is to use JSON. The following can be used to echo the array in JSON:

echo(json_encode($array));

See here for more information.

Then on the client side you can use the following function to decode the JSON to produce the same array:

decodedjson = JSON.parse(ajax.response);

Don't forget to wrap the client side code in an ajax call.

Hope this helps!

answered Jul 6, 2012 at 7:07

starbeamrainbowlabs

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scessor · Accepted Answer · 2012-07-06 07:20:39Z

2

You have to parse the json string before, e.g. with JSON.parse. Try (untested):

if (xmlhttp.readyState==4 && xmlhttp.status==200){
    var r=JSON.parse(xmlhttp.responseText);
    for (var i=0; i<r.length; i++){
        p.innerHTML= r[i] + '<br>';
    }

=== UPDATE ===

If you have to support very old browsers (e.g. less or equal then IE7) you should use libraries like Crockfords JSON2parser or jQuery (a huge lib with much more features).

edited Jul 6, 2012 at 7:20

answered Jul 6, 2012 at 7:04

scessor

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1 Comment

The Alpha Over a year ago

Be aware of older browsers, specially ie < 8.

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