jQuery-如何进行Ajax POST调用并附加数据

Question

I want to use the ajax() function to send a JSON variable and an integer to a page and append the retrieved data. This is where I'm at at the moment:

$.ajax({
    type: "POST",
    dataType: "json",
    url: "get_theme.php",
    data: {themestack:themes, iterator:theme_max_iterator},
    success: function(data){
        alert('Items added');
        $("#themes").append(data);
        ++IFRAMES_IN_DOM;
        ++theme_max_iterator;
    },
    error: function(e){
        alert(e.message);
    }
});  

themes is the JSON variable and theme_max_iterator is int . Currently I'm getting an alert of simply "undefined" so I'm wondering what is wrong?

EDIT:

In the log file I can see an error from get_theme.php :

PHP Warning:  json_decode() expects parameter 1 to be string, array given

And the line that caused it is:

$obj = $_POST['themestack'];
$json_data = json_decode($obj, true);

Which is strange since the JSON variable themestack is JSON .

Answer 1

I think you are getting an array in json_decode() try to encode json first then decode it like,

$obj = $_POST['themestack'];
if(is_array($obj)){// check if obj is an array then encode it first
   $obj = json_encode($obj);
}
$json_data = json_decode($obj, true);

Or before passing your data make it json like,

data: {themestack:JSON.stringify(themes), iterator:theme_max_iterator},

Answer 2

It looks like you are hitting the alert in your error: callback... I would suggest looking at the Request/response to see what the server returned.

Alternatively you could change the alert(e.message) to alert(JSON.stringify(e)) to find out what it tells you. But first thing mentioned is likely to more informative and closer to the issue than this later one.

Answer 3

if your AJAx is expecting JSON data, You must echo using "json_encode" in you php

    <?php
    $result = "blah blah"
    echo json_encode($result );
    ?>

Answer 4

I think your themes is a array. So, when you use $_POST['themestack'] in PHP, you got a array. And the jason_decode(...) function needs a JSON string as a argument.

Maybe you should change the following line to:

data: {themestack:JSON.stringify(themes), iterator:theme_max_iterator},

Or maybe you don't need jason_decode() and the $_POST['themestack'] object is what you want. You can treat it as an array and access it like $_POST['themestack'][0] .