Making a request with mootools is as easier as next lines are:

function doRequest(){

var data = "param1=1&param2=2";

new Request({
           url:'pagetorequest.java',
           method:'post',
           onSuccess: doOnSucess
         }).send(data);
}

function doOnSucess(response){
          alert("I am happy, and you?");
          alert("the response is:" + response);
}