PHP和jQuery中的Ajax调用

Question

This is my functions.php script containing the following code. The array is encoded into JSON.

functions.php

 $final['custom']['main'] = queryCustom($conn, $id);
 echo json_encode($final);

My global.js has the following code which makes an AJAX request in jQuery:

$.ajax({
            type: "POST",
            url: "functions.php", // file to reach Ajax call
            dataType: "json", 
            data: { 
                action: 'custom',
                id: id,
                  },
                success:
                function(data) {

                setCustom(data.custom);

I want to know what the data contains in function(data) ? The setCustom(data.custom) , what does this mean here? Can someone provide me an explanation of this please?

Answer 1

data contains an object literal provided by the server side json_encode(). It's been automatically parsed because the data type is set to json.

example:

PHP:

$final['custom']['main'] = queryCustom($conn, $id);
echo json_encode($final);

Will give the following json string (formatted for better understanding):

{
    "custom": {
        "main":[
            {
                "symbol":"MAP4",
                "official_ID":"112315"
            }
        ]
    }
}

The ajax call above is set to datatype json. jQuery knows if this datatype is set, it will automatically parse the string to an object literal.

Javascript:

$.ajax({
    type: "POST",
    url: "url.php", // file to reach Ajax call
    dataType: "json", 
    success: function(data) {
        var main = data.custom;
        console.log(main); // returns the child object with "main"
    }
});

data contains the initial object, custom is a child object of data and main is a child object of custom.

Answer 2

Success: A function to be called if the request succeeds. The function gets passed three arguments:

• Data Returned From The Server
• Status
• jqXHR (XMLHttpRequest Object)

In your PHP code you've added echo json_encode($final); which will be returned if the request is completed successfully. The response will be passed to data which you can later use in your front-end code.

You can read more about $.ajax() at http://api.jquery.com/jQuery.ajax/