A little javascript (script) to give you attribute updating with `prompt` & Rails UJS.

prompt-update.js

var jQuery   = jQuery,
    rails    = jQuery.rails,
    document = document;

(function($, rails, document) {
  "use strict";

  var PromptUpdate = {
    defaults: { name: 'value', method: 'put' },

    prompt: function(element) {
      var $element = $(element),
          options  = $.extend({}, this.defaults, $element.data(), { name: $element.attr('name') }),
          data     = prompt(options.prompt);

      if (data) {
        $element.data('params', options.name + '=' + data);
        $element.data('method', options.method);
        rails.handleRemote($element);
      }
    },

    _find: function(fn) {
      return function(list) {
        var i=list.length;
        while(i--) { if (fn(list[i])) { return list[i]; } }
      };
    },

    _newRailsSelector: function() {
      var appendNot = function(x) { return x + ':not([data-prompt])'; };
      return rails.linkClickSelector.split(',').map(appendNot).join(',');
    },

    moveRailsSelector: function() {
      var eventName     = 'click.rails',
          selector      = rails.linkClickSelector,
          handlerSearch = this._find(function(x) { return x.origType + '.' + x.namespace === eventName && x.selector === selector; }),
          handler       = handlerSearch($._data(document, 'events').click).handler,
          newSelector   = this._newRailsSelector();

      $(document).off(eventName, selector);
      $(document).on(eventName, newSelector, handler);
    }
  };

  PromptUpdate.moveRailsSelector();

  $(document).on('click', 'a[data-prompt]', function(e) {
    e.preventDefault();
    e.stopImmediatePropagation();
    PromptUpdate.prompt(this);
  });
}(jQuery, rails, document));

your-controller.rb

class YourController < ActionController::Base
  def update
    user = User.find(params[:id)
    if user.update_attributes(post_params)
      # probably return `something.js.erb` ...
    end
  end

  private
  def post_params
    params[:user].slice(:name)
  end
end

your-view.html.haml

# ...

= link_to 'Change Name', user_path(user), :name => 'user[name]', 'data-prompt' => 'New name?'