Bajax

Bajax its a very small (6k) and simple Ajax JavaScript library. This small library allows developers to make asynchronous calls to server regardless of the server-side language. It supports GET (default) and POST requests, can insert server-side response to DOM elements and supports debugging.

The Bajax library has some minor drawbacks. For instance, Bajax not seen any development in the last 6 years (since 2005). Of course, Ajax has not changed in this time and the library works great. The other thing is that the library lacks many examples and the README file is in Spanish.

However, here is a fast snippet how to use the Bajax JavaScript library to make GET and POST requests.

// Executed on completing the request
function say_result(data){
    alert(data);
}

// Call function 'sum' on PHP page 'math.php' 
bajax.execute('math.php','sum',say_result,{
    arg1:5,
    arg2:6
});

bajax.changeRequestType("POST"); // Make POST request

// Call function 'multiply' on PHP page 'math.php' 
bajax.execute('math.php','multiply',say_result,{
    arg1:5,
    arg2:6
});