Drupal 6 JavaScript and jQuery - Ebook-Cours.com

Drupal Behaviors
When drupal.js loads, it will evaluate whether the JavaScript implementation
supports DOM manipulation of the sort that jQuery and drupal.js rely upon. If the
correct functions exist then this flag will be set to true. Otherwise, the flag will be set
to false.
Internally, Drupal uses this flag to determine if behaviors are supported. If Drupal.
jsEnabled is false, then Drupal.attachBehaviors() doesn't attempt to attach any
behaviors. It just silently returns.
Also, Drupal uses this flag to set a cookie. If Drupal.jsEnabled is true, a cookie is
set which indicates that JavaScript support is sufficient. This way, server-side code
can send back appropriate responses based on a browser's JavaScript capabilities.
(This cookie is named has_js, and is available in PHP using $_COOKIE['has_js'].)
Feel free to use Drupal.jsEnabled whenever you are concerned that a browser
might not support the necessary JavaScript for DOM manipulations. But don't get
overly concerned about checking with the use of this flag. Most jQuery functions will
silently fail if JavaScript support isn't good enough, and the main Drupal features
(like behaviors) will be skipped as well.
The Drupal.checkPlain() function
(and the jQuery alternative)
The first function we will look at is the Drupal.checkPlain() function. If you have
already written some Drupal PHP code, you will probably recognize the name.
The Drupal.checkPlain() function takes a string and prepares it for display,
escaping symbols that have a special meaning in HTML. While the use of the term
check implies that this will return a Boolean value (true if the text is plain, false if
otherwise), it actually performs the escaping, and returns the escaped string.
So what does it escape? Let's look at an example. While viewing a node on our
Drupal system, we can use the Firebug console to manipulate the document:
>>> myString = "A string with HTML embedded.";
"A string with HTML embedded."
>>> $('.node .content').html(myString);
Object length=1
The first line creates a new string named myString. Note that the contents of this
string contain embedded HTML: A string with HTML embedded
In the second line we use jQuery to find the main content section for the node
displayed on the current page, and replace the existing contents of that section
with the value of myString. Since this involves a little bit of new jQuery, let's look
at it closely.
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This material is copyright and is licensed for the sole use by Richard Ostheimer on 18th June 2009
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