HI all,
I have problem to understand how sending and comunication between jqeury and php goes. I have simple task. I need to send json object to php and than do some stuff with it (json_decode, make it XML, save to database...). I have index.php with button SAVE (id = "save") and external .js file:
...
var obj; //there is something in

$("#save").on('click', function(){
$.ajax({
type: "POST",
url: "./save.php",
data: {"obj"bj},
success: function()
{
alert("Changes saved.");
}
});
});

Third file is simple external php file (save.php):

<?php

$obj = json_decode($_POST['xmlObject']);
echo $obj;

?>


The strange thing is that alert("Changes saved.") occures, but there is no evidence of processing echo $obj.
Please tell me what I am doing wrong :/. One thing I dont really understand is how php file knows when it should be executed.

Thanks a very lot for any answer.