jQuery: Work with text nodes and comment nodes

Nearly all jQuery traversal functions ignore elements that are not HTML tags.

To work with other type of nodes (like text, comment or CDATA sections) you need to:

  • Retrieve child nodes contents() (which behaves like children() except that it returns all types of child nodes)
  • Filter manually using either plain Javascript or jQuery's filter() method

Example

Let's write a function that takes a jQuery element and returns an array of all child nodes that are text nodes:

function selectTextNodes($container) {
  retu...

Rest-ORM for Angular: Restmod

Restmod creates objects that you can use from within Angular to interact with your RESTful API.

6 front-end techniques for Rails developers. Part I: From big ball of mud to separated concerns

Amazing guide how to divide a ball of Javascript spaghetti distinct separate layers (model, view, controller, backend adapter).

It does not use a Javascript framework.

jQuery and cross domain AJAX requests

When making cross-domain AJAX requests with jQuery (using CORS or xdomain or similar), you will run into issues with HTTP headers:

  • jQuery will not set the X-Requested-With header. On your server, requests will not look like AJAX requests (request.xhr? will be false).
  • jquery-ujs will not set CSRF headers.

This is by design and improves secu...

Rails Assets

Automatically builds gems from Bower packages (currently 1700 gems available). Packaged Javascript files are then automatically available in your asset pipeline manifests.

Why we're not using it

At makandra we made a choice to use bower-rails instead. While we believe Rubygems/Bundler to be superior to Javascript package managers, we wanted to use something with enough community momentum behind it that it won't go away in 10 years...

SudoSlider: a jQuery slider

SudoSlider is a simple yet powerful content slider that makes no (or very few) assumptions about your markup and is very customizable.

You can basically embed any HTML into the slides, so you can mix images, videos, texts, and other stuff.

Check out the demos.

Please note:

  • There is a ton to configure. Check the demos and read the docs.
  • It does not bring styles for prev/next links etc, so you need to style controls yourself (which I consider to b...

JavaScript: Calling a function with a variable number of arguments

This card describes how to pass an array with multiple element to a JavaScript function, so that the first array element becomes the first function argument, the second element becomes the second argument, etc.

Note how this is different from passing the entire array as the first argument. Compare these two different ways of calling fun() in Ruby:

# Ruby
array = [1, 2, 3]
fun(array)  # same as fun([1, 2, 3]) (1 argument)
fun(*array) # same as fun(1, 2, 3)   (3 arguments)

Depending on your culture the spreading of array eleme...

Cucumber step to manually trigger javascript events in Selenium scenarios (using jQuery)

When you cannot make Selenium trigger events you rely on (e.g. a "change" event when filling in a form field), trigger it yourself using this step:

When /^I manually trigger a (".*?") event on (".*?")$/ do |event, selector|
  page.execute_script("jQuery(#{selector}).trigger(#{event})")
end

Note that this only triggers events that were registered through jQuery. Events registered through CSS or the native Javascript registry will not trigger.

Tearing Down Capybara Tests of AJAX Pages

An all-in-approach to fix the problem of pending AJAX requests dying in the browser when the server ends a test or switches scenarios.


We were able to work around this issue in most projects by doing this instead:

After '@javascript' do
  step 'I wait for the page to load'
end

patbenatar/jquery-nested_attributes

jQuery plugin that makes it easy to dynamically add and remove records when using ActiveRecord's nested attributes.

Get the last leaf of a DOM tree (while considering text nodes)

I use this to simulate the (non-existing) :last-letter CSS pseudoclass, e. g. to insert a tombstone at the end of an article:

findLastLeaf = ($container) ->
  $children = $container.children()
  if $children.length == 0
    $container
  else
    $lastChild = $children.last()
    $lastContent = $container.contents().filter(->
      # Only return nodes that are either elements or non-empty text nodes
      @nodeType == 1 || (@nodeType == 3 && _.strip(@nodeValue) != '')
    ).last()
...

Making media queries work in IE8 and below

When using @media CSS queries, Internet Explorer 8 and below will fail to respect them.

Though there are several options (like mediatizr and css3-mediaqueries), Respond.js was the only one that worked for me.


If you do not want to pollute your application's default JS file with Respond.js, simply:

  1. Create an extra JS file (like media_queries_polyfill.js) that loads Respond.js:

    //= require respond-1.4.2
    
  2. Make sure it's added to config.assets.precompile

  3. Embed that JS fi...

Why you might not need MVC with React.js

React.js is a relatively new Javascript templating engine that has two-way-bindings like AngularJS or Batman. The interesting idea here is that React keeps a virtual copy of the DOM tree in memory, and when you re-render, it only changes the DOM as little as required. That means if you re-render a list with 1000 items, and only one item has changed, the browser-DOM will only remove and add a single element instead of 1000 elements. This makes React.js views insanely fast.

The attached article proposes that React.js is so fast that you don...

Sticky table header with jQuery

When you want the table headers to always stay around (e.g. because that table is huuuge), use the code below.

Style

table.fixed_table_header{
  position: fixed;
  top: 0;
  width: auto;
  display: none;
  border: none;
  margin: 0;
}

Javascript

;(function($) {
   $.fn.fixHeader = function() {
      return this.each(function() {
         var $table = $(this),
            $t_fixed;

         function init() {
            $t_fixed = $table.clone();
            $t_fixed.find('tbody').remove().end().addClass('fi...

Restangular: How to remove an element from a collection without breaking restangular

So you have a restangular collection and you want to remove an element from it, after you've successfully deleted it from the server.

The README suggests to say something like $scope.users = _.without($scope.users, user). While that works at first glance (the element is no longer in your collection), it will break horribly when you want to use restangular's attributes on that collection.

This...

AngularJS directive to format a text with paragraphs and new lines

If you are using Angular and want something like Rails' simple_format which HTML-formats a plain-text input into paragraphs and line breaks, this directive is for you.

Any HTML fragments inside that text will still be escaped properly.

Use it like this, where your text attribute specifies something available in your current scope:

<simple-format text="email.message"></simple-format>

This is the directive, in CoffeeScript syntax:

@app.directive 'simpleFor...

Ruby: How to camelize a string with a lower-case first letter

If you want to do JavaScript-style camelization, ActiveSupport's String#camelize method can actually help you out. Simply pass a :lower argument to it.

>> 'foo_bar_baz'.camelize
=> "FooBarBaz"
>> 'foo_bar_baz'.camelize(:lower)
=> "fooBarBaz"

Listening to bubbling events in Prototype is easy

If you come across an (older) application that is using Prototype instead of jQuery, you may often see events bound to single elements only, like this:

$('foo').observe('change', updateThings);
$('bar').observe('change', updateThings);
$('baz').observe('change', updateThings);

If you are calling only one method in each case, this is unnecessarily ugly. Also, when your page contents have been replaced via AJAX (like sections of a form after choosing something), those event hooks will no longer wo...

Why your previous developer was terrible

When you, as a developer, look at the choices used to build a particular application, you’re blown away at the poor decisions made at every turn. “Why, oh why, is this built with Rails when Node.js would be so much better?” or “how could the previous developer not have forseen that the database would need referential integrity when they chose MongoDB?” But what you may not realize is that you are seeing the application as it exists today. When the previous developer (or team) had to develop it, they had to deal with a LOT of unknowns. They...

Ruby on Rails 4 and Batman.js

Batman is an alternative Javascript MVC with a similar flavor as AngularJS, but a lot less features and geared towards Ruby on Rails.

The attached link leads to a tutorial for a small blog written with Rails / Batman.js.

I'm collecting other Batman.js resources in my bookmarks.

JavaScript: How to log execution times to your browser console

If you are trying to inspect timings in JavaScript, you can use console.time and console.timeEnd which will write to your browser console.

Example:

console.time('lengthy calculation');
lengthyCalculation();
console.timeEnd('lengthy calculation');

lengthy calculation: 1.337ms

Note that this allows using console.timeEnd in another context which is helpful when you are doing things asynchronously, or just in different places.

Works in all browsers, including recent Internet Explorers. For older IEs, you may activate...

Techniques for authentication in AngularJS applications

Article about implementing authentication (current_user) and authorization (access rights) in AngularJS.

Has an surprising amount of practical and understandable code.

Cucumber: Wait until CKEditor is loaded

I had to deal with JavaScript Undefined Error while accessing a specific CKEditor instance to fill in text.

Ensure everything is loaded with

patiently do
  page.execute_script("return isCkeditorLoaded('#{selector}');").should be_true
end

Example

The fill in text snippet for Cucumber:

When /^I fill in the "([^\"]+)" WYSIWYG editor with:$/ do |selector, html|
  patiently do
    page.execute_script("return isCkeditorLoaded('#{selector}');").should be_true
  end
  html.gsub!(/\n+/, "") # otherwise: unterminated string lit...

Howto prompt before accidentally discarding unsaved changes with JavaScript

Ask before leaving an unsaved CKEditor

Vanilla JavaScript way, but removes any other onbeforeunload handlers:

  $(function(){
    document.body.onbeforeunload = function() {
      for(editorName in CKEDITOR.instances) {
        if (CKEDITOR.instances[editorName].checkDirty()) {
          return "Unsaved changes present!"
        }
      }
    }
  }

A robuster implementation example

Note: Don't forget to mark the 'search as you type' forms with the skip_pending_changes_warning class.

var WarnBeforeAccidentallyDiscard...