text: var Proxy = Proxy || {};
  
  Proxy.login = (username, password, callback) => {
      let AJAX_req = new XMLHttpRequest();
      let url = 'UsuarioServlet?action=login';
      AJAX_req.open("POST", url, true);
      AJAX_req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      AJAX_req.onreadystatechange = function() {
          if (AJAX_req.readyState === 4 && AJAX_req.status === 200){
              let response = JSON.parse(AJAX_req.responseText);
              if(callback)    
                  callback(response);
          }
      };
      AJAX_req.send("username=" + username + "&password=" + password);
  };
  
  Proxy.logout = (callback) => {
      let AJAX_req = new XMLHttpRequest();
      let url = 'UsuarioServlet?action=logout';
      AJAX_req.open("POST", url, true);
      AJAX_req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      AJAX_req.onreadystatechange = function() {
          if (AJAX_req.readyState === 4 && AJAX_req.status === 200){
              let response = JSON.parse(AJAX_req.responseText);
              if(callback)    
                  callback(response);
          }
      };
      AJAX_req.send();
  };
  
  Proxy.searchText = (texto, callback) => {
      let AJAX_req = new XMLHttpRequest();
      let url = 'SugerenciaServlet?action=searchText';
      AJAX_req.open("POST", url, true);
      AJAX_req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      AJAX_req.onreadystatechange = function() {
          if (AJAX_req.readyState === 4 && AJAX_req.status === 200){
              let response = JSON.parse(AJAX_req.responseText);
              if(callback)    
                  callback(response);
          }
      };
      AJAX_req.send("texto=" + texto);
  };
  
  Proxy.addSugerencia = (texto, callback) => {
      let AJAX_req = new XMLHttpRequest();
      let url = 'SugerenciaServlet?action=addSugerencia';
      AJAX_req.open("POST", url, true);
      AJAX_req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      AJAX_req.onreadystatechange = function() {
          if (AJAX_req.readyState === 4 && AJAX_req.status === 200){
              let response = JSON.parse(AJAX_req.responseText);
              if(callback)    
                  callback(response);
          }
      };
      AJAX_req.send("texto=" + texto);
  };
  