Question

Here’s an example taken from
http://docs.jquery.com/API/1.1/AJAX#.24.post.28_url.2C_params.2C_callback_.29

 $.ajax({
   type: "POST",
   url: "some.php",
   data: "name=John&location=Boston",
   success: function(msg){
     alert( "Data Saved: " + msg );
   }
 });

So does

data: "name=John&location=Boston"

assign the value ‘John’ to the variable $name and ‘Boston’ to $location in some.php ?

Or what does it do…?
On the website they simply say

“Save some data to the server and notify the user once it’s complete.“

Answer 1

It makes the browser request the URL

some.php

with the message body:

name=John&location=Boston

These will appear as $_POST['name'] and $_POST['location'].

Don’t build your data strings by hand though. If you are using jQuery anyway, let it build them for you. It will handle escaping for you automatically.

data: { 
    "name": "John", 
    "location": "Boston" 
},