AJAX is one of the main reasons to use a Javascript library such as jQuery. See how simple it is to perform a previously difficult task that required complex browser specific code to preform reliably and was prone to simple mistakes. Implement basic AJAX requests using jQuery's built in methods which make it extremely simple to send an asynchronous request to a server, gather the returned data, and insert it into the page.

Example code:

// AJAX Live Function
$('.content p').live('mouseenter mouseleave',
  function() {
    $(this).toggleClass('hilight');
  }
);

// AJAX Example
$('.node_read_more a').click(function() {
  var url = $(this).attr('href');
  var link = this;

  $.ajax({
    url: url,
    success: function(data) {
      var $fullContent = $('#content-output .content', data);
      var html = $fullContent.html();
      $(link).closest('div.node').find('div.content').html(html);
      $(link).hide();
    }
  });
  return false;
});

In its short history, jQuery has revolutionized front-end web development, making it faster, easier, and more rewarding to write JavaScript – allowing easier selection and manipulation of HTML elements, and ensuring that scripts work across the ever increasing landscape of browsers and operating systems.

Nate Haug and Jeff Robbins show many hands-on examples demonstrating how to use jQuery's simple syntax to choose and manipulate HTML elements, traverse the document object model (DOM), and to attach event handlers which can react to user interaction with the page.

In this video, Jeff and Nate introduce themselves and the agenda for this series, including Selectors, Effects, and AJAX.

YAML, which stands for YAML Ain't Markup Language, is a human-readable data serialization format that's been widely adopted in a variety of use cases in Drupal. Anyone wanting to write modules, or themes, for Drupal will need to understand YAML syntax. Even site builders are likely to encounter YAML at least in passing as YAML is the data-serialization format of choice for Drupal's configuration management system. Good thing it's pretty easy to learn even with the most basic of programming backgrounds.

This tutorial will look at the YAML data format and provide examples of how to write and read YAML. Starting with an introduction to the language's syntax and some of the strengths of YAML. Then looking at the difference between scalar data types like strings and integers, and collection data types like lists and associative arrays.

Since YAML in the Drupal world is read into PHP and ultimately becomes a PHP data structure that we can use in our own code we'll also look at how the YAML we write in a .yml file is represented in PHP data types. To do this we'll use the YAML Sandbox module that provides a handy textarea into which we can type YAML and have it parsed into PHP data structures.

Learning objectives

• Explain what YAML is and its strengths as a data serialization format
• Create scalar key/value pairs in YAML
• Create lists, and associative arrays using YAML collections
• Understand how the YAML you write is represented in PHP

Tips

• In Drupal, use the .yml extension and not .yaml
• Ensure your code editing application is configured to use spaces (preferably 2 spaces, as per Drupal coding standards), not the tab character when the TAB key is pressed. If you have tab characters in a YAML file within a Drupal environment, a fatal PHP error will be thrown and you'll see a White Screen of Death (WSOD).
• Copy and paste from an existing YAML file to ensure the formatting is correct, and edit from there.

Additional resources

• http://www.yaml.org
• YAML Sandbox module
• Find other tutorials and external resources related to YAML on our YAML topic page (Drupalize.Me)