Within an event handler, there are multiple methods to cancel event propagation, each with different semantics.

• event.preventDefault()

  Only prevents the default browser behavior for the click, i.e. going to a different url or submitting a form.

  When invoked on a touchstart event, this also prevents mouse events like click to be triggered.

• event.stopPropagation()

  Prevents the event from bubbling up the DOM.

• `event.st...

Back when Steak was first released, Capybara didn’t have any of the nice RSpec helpers it does now. A lot has changed since. Besides the helpers, it got its own RSpec acceptance testing DSL recently, essentially eating Steak’s functionality and turning it into a complete acceptance testing solution (on top of RSpec).

The information in this card is only relevant for Rails 2.3-era apps.

This note gives a quick introduction into caching methods (page caching, action caching and fragment caching) in rails and describes some specific problems and solutions.

The descriptions below are valid for Rails 2 and 3. Recently, caching with timestamp- or content-based keys has become more popular which saves you the pain of invalidating stale caches.

How to enable/disable caching

To enable or disable caching in rails you ca...

Liquid Canvas is a JavaScript library which allows you to draw inside an HTML canvas element with an easy yet powerful description language.

It can be used to add graphics to your web page without ever touching an image creation tool such as The Gimp, Inkscape or Photoshop.

Check out the Demo and the basic example and then download version 0.3.

Specify these gem versions in your Gemfile:

gem 'cucumber', '~> 1.3.0'
gem 'cucumber-rails', '= 0.3.2' # max version for Rails 2
gem 'capybara', '< 2' # capybara 2+ requires Rails 3
gem 'mime-types', '< 2' # dependeny of capybara
gem 'nokogiri', '< 1.6' # dependency of capybara
gem 'rubyzip', '< 1' # dependency of selenium-webdriver, rubyzip 1+ requires Ruby 1.9
gem 'cucumber_factory'
gem 'database_cleaner', '< 1'
gem 'cucumber_spinner', '~> 0.2.5'
gem 'launchy', '~> 2.1.2'

With these versions set, `...

The shell variable PS1 holds your bash prompt. You might want to change it to serve your needs best. Here is how to:

General

• non-printing escape sequences in your prompt have to be inclosed in \[\e[ and \] so your shell can correctly count its prompt's length
• we recommend to highlight your prompt on production machines
• you can also [show different root prompts for each user](https://makandracards.com/makandra/9569-get-the-username-w...

Add deprecation warnings and their solution or link to available solutions.

Global access to Rake DSL methods is deprecated. Please include Rake::DSL into classes and modules which use the Rake DSL methods.

Open your Rakefile and add the following line above YourApp::Application.load_tasks:

YourApp::Application.class_eval do
  include Rake::DSL
end

Use of ole/file_system is deprecated. Use ole/storage (the file_system api is recommended and enabled by default)...

JavaScript Garden is a growing collection of documentation about the most quirky parts of the JavaScript programming language. It gives advice to avoid common mistakes, subtle bugs, as well as performance issues and bad practices that non-expert JavaScript programmers may encounter on their endeavours into the depths of the language.

JavaScript Garden does not aim to teach you JavaScript. Former knowledge of the language is strongly recommended in order to understand the topics covered in this guide

The attached RSpec matcher exist_in_database checks if a given record still exists in the database and has not been destroyed:

describe Ticket do
  describe '.purge_expired' do
    fresh_ticket = Ticket.create(:expiry => Date.tomorrow)
    expired_ticket = Ticket.create(:expiry => Date.yesterday)
    Ticket.purge_expired
    fresh_ticket.should exist_in_database
    expired_ticket.should_not exist_in_database
  end
end

Note that there is also [ActiveRecord::Base#destroyed?](http://apidock.com/rails/ActiveRecord/Base/destroyed...

When you click a link or a press a button on a Selenium-controlled browser, the call will return control to your test before the next page is loaded. This can lead to concurrency issues when a Cucumber step involves a Selenium action and a Ruby call which both change the same resources.

Take the following step which signs in a user through the browser UI and then sets a flag on the user that was just signed in:

Given /^the user "([^"]*)" signed in (\d) days ago$/ do |name, days|
  visit new_session_path
  fill_in 'Username', :w...

Around the time in my life when I stopped ordering drinks made with more than one ingredient, I was woken up for the last time by a hypochondriac Nagios monitoring installation. If you are on-call long enough, you cultivate a violent reaction to the sound of your cell phone's text message alert. If your monitoring is overconfigured, that reaction boils over hastily, as it will interrupt you during meals, sex, sleep — all of the basics — with the excruciating operational details of your web site.

I've since developed, with the help of some n...

Pressing the ? key will display a list of keyboard shortcuts. Available shortcuts are:

|search |/|
|help|?|
|add story|a|
|toggle backlog|<Shift> + b|
|toggle charts (graphs)|<Shift> + g|
|toggle current|<Shift> + c|
|toggle done|<Shift> + d|
|toggle history|<Shift> + h|
|toggle icebox|<Shift> + i|
|toggle my work|<Shift> + w|
|toggle labels & searches|<Shift> + l|

This is awesome.

"Wallaby" is the codename for an experimental technology that converts the artwork and animation contained in Adobe® Flash® Professional (FLA) files into HTML. This allows you to reuse and extend the reach of your content to devices that do not support the Flash runtimes. 

If you have content inside a page that is hidden by CSS, the following will work with Selenium, but not when using the Rack::Test driver. The Selenium driver correctly only considers text that is actually visible to a user.

Then I should not see "foobear"

This is because the Rack::Test driver does not know if an element is visible, and only looks at the DOM.

Spreewald offers steps to check that an element is hidden by CSS:

Then "foo" should be hidden

You can also check that an el...

If you use a form (or form fields) multiple times inside one view, Rails will generate the same id attributes for fields again.

This card presents you with a way to call something like

- form_for @user, :prefix => 'overlay' do |form|
  = form.text_field :email

and get this as HTML:

<input name="user[email]" id="overlay_user_email" (...) />

You can also put a :prefix into a field's options. Note how only the id but not the name changes as we would not want to pass an overlay_user[email] param to the controller. Sett...

Flash movies (.swf files) can talk with Javascript code embedded in the same HTML page. There are two ways to do this:

• The preferred way is to use the ExternalInterface class to call Javascript functions from ActionScript, and to bind ActionScript functions to the Flash movie's DOM element so they can be called from Javascript.
• The deprecated way is to use the global [fscommand](http://help.adobe....

Note: For PostgreSQL you should use advisory locks. For MySQL we still recommend the solution in this card.

If you need to synchronize multiple rails processes, you need some shared resource that can be used as a mutex. One option is to simply use your existing (MySQL) database.

The attached code provides a database-based model level mutex for MySQL. You use it by simply calling

Lock.acquire('string to synchronize on') do
  # non-th...

Sometimes you want to run a command forever, e.g. to compile a haml to html file on the console. Use this:

$ while(true) do haml index.haml index.html; sleep 1.5; done

Javascript that implements client-side hyphenation of HTML-Documents.

You know Firebug as a Firefox extension but there is also a "Lite" version which runs purely off JavaScript.

Though all major browsers offer inspection tools you may like the Firebug style. Also, for me this is a lot better than the IE8 developer tools -- and it works in older versions of IE, too.

Get the bookmarklet over at http://getfirebug.com/firebuglite#Stable. It usually loads the JavaScript code from a remote server but you can also download it to have it run locally. If adding the bookmarklet does not work in IE, add a new book...

jQuery plugin to register callback functions to keyboard shortkuts. Keyboard events in vanilla Javascripts are super-painful to work with, so hopefully this library can help.

Note: Consider not doing this. Use form models or vanilla methods instead.

The :conditions option for Rails associations cannot take a lambda. This makes it hard to define conditions that must be evaluated at runtime, e.g. if the condition refers to the current date or other attributes.

A hack to fix this is to use faux string interpolation in a single-quoted :conditions string:

class User < ActiveRecord::Base
  has_many :contracts
  has_one :current_contract, :class_name => 'Contract', :conditions => '...

The difference between .bind(), .live(), and .delegate() is not always apparent. Having a clear understanding of all the differences, though, will help us write more concise code and prevent bugs from popping up in our interactive applications.

This card describes a Cucumber step that lets you say:

When I perform basic authentication as "username/password" and I visit the admin area

The path component ("... the admin area") is parsed through your path_to helper in features/support/paths.rb.

Capybara

The step definition is part of Spreewald. The step has been tested with multiple versions of Capybara, Rack::Test and Selenium.

Webrat (legacy)

This is a simpler version of the step above:

When /...