accessing the jquery function after success call? - php

Question

jQuery(function ($) {
/* fetch elements and stop form event */
$("form.follow-form").submit(function (e) {
/* stop event */
e.preventDefault();
/* "on request" */
$(this).find('i').addClass('active');
/* send ajax request */
$.post('listen.php', {
followID: $(this).find('input').val()
}, function () {
/* find and hide button, create element */
$(e.currentTarget)
.find('button').hide()
.after('<span class="following"><span></span>Following!</span>');
});
});
});
i want to know what when i process the mysql query in the listen.php file, how deos it get the success message back, and then perform the change after?

Answer 1

UPDATE
PHP code:
<?php
if ( $_POST['action'] == 'follow' ) {
$json = '';
if ( $_POST['fid'] == "2" ) {
$json = array( array( "id" => 1 , "name" => "luca" ),
array( "id" => 2 , "name" => "marco" )
);
}
echo json_encode($json);
}
?>
jQuery code:
$.ajax({
type: 'POST',
url: 'listen.php',
data: 'action=follow&fid=' + 2, //$(this).find('input').val(),
success: function(data) {
var obj = $.parseJSON(data);
for ( var i = 0; i < obj.length; i++ ) {
alert( obj[i].id + ' ' + obj[i].name )
}
},
complete: function(data) {
//alert(data.responseText);
},
error: function(data) {
alert(data);
}
});

Answer 2

it's XMLHTTP Object that is responsible behind the scene.

Answer 3

your php script should output text... so lets say the query works output "YES" if it doesn't output "NO" then use this function in your $.post():
function (data) {
if(data=="YES"){
// worked
}
else{
// didn't work
}
}