about the jquery ajax and with php

After reading ajax from:

http://api.jquery.com/jquery.ajax/ I am totally confused.

It was so complex and I don't know anything about xml I just know few about php and jquery but I was confused a lot.

i don't know how to work ajax with php...

and people talk about handlers call backs etc i don't know anything what are they talking..

and when i work with php and submit thorugh php what is going to be $_POST["name"] is there $_COOKIE or some super globals

I just wanna know what should go in PHP files

Solution

Here is a basic example that will let input your name, and PHP will return it in a sentence and let it be displayed.

Here is the html that I name foo.html:

<html>
<head>
<script src="//code.jquery.com/jquery-1.11.0.min.js"></script>
<script type="text/javascript">
function callPHP() {
        $.ajax({
                type: "POST",
                url: "foo.php",
                data: { name: $('#namefield').val() }
        })
          .done(function(response) {
                $('#response').html(response);
        });
}
</script>
</head>
<body>
<span id="response"></span>
<br/>
Name: <input id="namefield" type="text"><button onclick="callPHP()">Submit</button>
</body>

Here is the PHP code that I named foo.php:

<?php
if(!empty($_POST['name'])) {
        echo 'Your name is '.$_POST['name'];
} else {
        echo 'I did not get anything';
}
?>

The callPHP function takes the value of the input field and assigns it to post value with data: { name: $('#namefield').val() } and assign it to the POST field of name. The response is handled with the done(function(response){}) anonymous function and assigns the span value to it.

I hope this helps.