app.rb

require 'rubygems'
require 'sinatra'

get '/' do
  haml :test
end

get '/test' do
  params[:callback] + '({ sonda: ' + params[:sonda] + '})'
end

post '/test' do
  params[:callback] + '({ sonda: ' + params[:sonda] + '})'
end

put '/test' do
  params[:callback] + '({ sonda: ' + params[:sonda] + '})'
end

delete '/test' do
  params[:callback] + '({ sonda: ' + params[:sonda] + '})'
end

post '/test' do
  params[:callback] + '({ sonda: ' + params[:sonda] + '})'
end

test.haml

%html
  %head
    %script{:src=> 'http://code.jquery.com/jquery-1.4.2.min.js'}
    %script{:src=> '/test.js'}
  %body
    %button.GET Try GET
    %button.POST Try POST
    %button.PUT Try PUT
    %button.DELETE Try DELETE

test.js

(function($){
  $(function ready(){

    $('button').click(function send_by_method(){
      $.ajax({
        url: '/test',
        type: $(this).attr('class'),
        dataType: 'jsonp',
        data: {
          sonda: '123456'
        },
        success: function ok(data){
          console.log("SUCCESS", 'sonda', data.sonda)
        },
        error: function error(){
          console.log("ERROR")
        }
      });
    });

  });
})(jQuery);