WCLV13 JavaScript

Weaving JavaScript
-- in and out of --

WordPress
WordCamp Las Vegas 2013
slides: http://www.slideshare.net/jeffreyzinn/wclv13-javascript
code: https://gist.github.com/jeffreyzinn/7953881

Friday, December 13, 13

Jeffrey Zinn
• Co-founder of Pixel Jar
• WordCamp OC co-organizer
• AdSanity co-developer
• @jeffreyzinn
• jeff@jzinn.us
surfer, WordPress fanboy,
avid backpacker, euro gamer,
soccer hooligan, traveler,
voracious coffee drinker


Need To Know
1. JavaScript
2. Functions
3. Actions


Topics
1. Loading JavaScripts - making
JavaScripts available to themes, plugins
and code
2. Available Libraries - JavaScripts that
are already available in a default
WordPress installation
3. Using CDNs - load JavaScripts from nonlocal sources
4. Localize Script - making data from PHP
available in JavaScript

1. Loading Javascript
making JavaScripts available to themes,
plugins and code


Example 1
What we are doing:
Load a custom JavaScript called custom.js from
my theme’s /js directory.

load
me


Do Not...
...simply add a <script> tag into a template or
header ﬁle
<head profile="http://gmpg.org/xfn/11">
<meta http-equiv="Content-Type" content="text/html;
charset=UTF-8" />
<title>WP Starter Setup — Just another WordPress site</title>
<link rel="stylesheet" href="http://wp.start/wp-content/
themes/billerickson-BE-Genesis-Child-c73d97a/style.css"
type="text/css" media="screen" />
<script type='text/javascript' src='http://wp.start/wpincludes/js/jquery/jquery.js?ver=1.7.2'></script>
<script type="text/javascript" src="http://wp.start/wpcontent/themes/billerickson-BE-Genesis-Child-c73d97a/js/
custom.js"></script>
</head>


Do Not...
...echo out a <script> tag using using the
wp_head/wp_footer action

<?php
add_action( 'wp_head', 'load_my_script' );
function load_my_script() {
$src = get_stylesheet_directory_uri() . '/js/custom.js’;
echo '<script type="text/javascript" src="' . $src . '”></script>';
}
?>


Functions
• wp_register_script() - get ready to use a
script (but don’t load it up just yet)

• wp_deregister_script() - remove a
registered script

• wp_enqueue_script() - load that script
into my theme/plugin so I can use it

• wp_dequeue_script() - remove an
enqueued script


The Process
1. Use the wp_enqueue_scripts action to
load in your selected JavaScripts
2. Stage a script by calling the
wp_register_script function
3. Load the script from #2 using the
wp_enqueue_script function
Often on functions.php, but could be
elsewhere in your theme or plugin code.

wp_register_script()
Description:
Safe way of registering JavaScripts in
WordPress for later use:
<?php
wp_register_script
( $handle, $src, $deps, $ver, $in_footer );
?>
string
string
array
string
boolean
give the file
a unique
nickname
(required)


where is
the file

what other
files have to
be loaded
first

the
script’s
version
number

should WP
try and load
this in the
footer

wp_register_script()
Description:
Safe way of registering JavaScripts in
WordPress for later use:
<?php
wp_register_script
( $handle, $src, $deps, $ver, $in_footer );
?>
string
string
array
string
boolean

Note:
admin_enqueue_scripts to call it on the admin side, or use
login_enqueue_scripts for login screens.


Example 1.1
What we are doing:
Load a custom JavaScript called custom.js from
my theme’s /js directory.
<?php
add_action( 'wp_enqueue_scripts', 'simple_load_script' );
function simple_load_script() {
$src = get_stylesheet_directory_uri() . '/js/custom.js' ;
wp_register_script( 'custom-script', $src, array( 'jquery' ), '1', TRUE );
}
?>

wp_enqueue_script( 'custom-script' );


Example 1.2
What we are doing:
Register and enqueue custom.js as separate
actions.
<?php
/** Register JavaScripts **/
add_action( 'wp_enqueue_scripts', 'custom_register_scripts' );
function custom_register_scripts() {
}
/** Enqueue JavaScripts **/
add_action( 'wp_enqueue_scripts', 'custom_enqueue_scripts' );
function custom_enqueue_scripts() {
}
?>


Example 1.3
What we are doing:
Load custom.js conditionally for pages only.
<?php
add_action( 'wp_enqueue_scripts', 'custom_script_for_pages' );
function custom_script_for_pages() {

}
?>

if( is_page() )


Example 1.4
What we are doing:
Load custom.js without registering.
<?php
add_action( 'wp_enqueue_scripts', 'custom_script_enqueue' );
function custom_script_enqueue() {
wp_enqueue_script( 'custom-script', $src, array( 'jquery' ), '1', TRUE );
}
?>


(works with styles too)
• wp_register_style()
• wp_deregister_style()
• wp_enqueue_style()
• wp_dequeue_style()


2. Available Libraries
JavaScripts that are already available in
a default WordPress installation


Available Libraries
Script

Handle

SWFUpload

swfupload

jQuery UI Core

jquery-ui-core

jQuery UI Accordion

jquery-ui-accordion

jQuery UI Datepicker

jquery-ui-datepicker

ThickBox

thickbox

jQuery Hotkeys

jquery-hotkeys

...plus many other scripts
http://codex.wordpress.org/Function_Reference/
wp_enqueue_script#Default_scripts_included_with_WordPress

Example 2.1
What we are doing:
Load and use jQuery UI Draggable, which is preregistered.
<?php
add_action( 'wp_enqueue_scripts', 'enqueue_draggable' );
function enqueue_draggable() {
wp_enqueue_script( 'jquery-ui-draggable' );
}
?>


Example 2.2
What we are doing:
Load a custom script called draggable.js in /js
directory that uses jQuery UI Draggable and
make our widgets draggable!
<?php
/** Corresponding JavaScript: https://gist.github.com/3718542

**/

add_action( 'wp_enqueue_scripts', 'custom_draggable_script' );
function custom_draggable_script() {
$src = get_stylesheet_directory_uri() . '/js/draggable.js' ;
wp_register_script( 'custom-draggable-script', $src,
array( 'jquery','jquery-ui-draggable' ), '1', TRUE );
wp_enqueue_script( 'custom-draggable-script' );
}
?>

3. Using CDNs
load JavaScripts from non-local sources


Example 3.1
What we are doing:
Load jquery from an external source.
<?php
add_action( 'wp_enqueue_scripts', 'load_jquery_from_googleapis' );
function load_jquery_from_googleapis() {
wp_deregister_script( 'jquery' );
$src = 'http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js';
wp_register_script( 'jquery', $src, array(), '1.10.2' );
wp_enqueue_script( 'jquery' );
}
?>


Example 3.1
What we are doing:
Load jQuery from an external source.
<?php
}
?>


Keep same handle
for dependencies

Example 3.1
What we are doing:
Load jquery from an external source.
<?php
}
?>


Be careful of version #,
is it still compatible with
WP and your stuff?

4. Localize Script
making data from PHP
available in JavaScript


Do Not...
...use PHP to build JavaScript code
<?php
add_action( 'wp_head', 'build_my_script' );
function build_my_script() {
global $current_user;
get_currentuserinfo();
echo
echo

"rn";
'<script type="text/javascript">' . "rn";
echo "t" . 'var userid = "' . esc_js( $current_user->ID ) . '";';
echo "rn";
echo "t" . 'var fname = "' . esc_js( $current_user->user_firstname ) . '";';
echo "rn";
echo '</script>' . "rn";

}
?>


wp_localize_script()
Description:
Send PHP data into the JavaScript data world.
Usage:
<?php
wp_localize_script( $handle, $object_name, $l10n );
?>
string
string
array
nickname
of script to
send data to
(required)


what to call
the object
when it is
in the script
(required)

what data
to send to
the script
(required)

Description:
Usage:
<?php
?>

Note:
wp_localize_script() must be called AFTER the script it's being
attached to has been enqueued. It doesn't put the localized
script in a queue for later queued scripts.


Description:
Usage:
<?php
?>

Also Note:
$l10n (array) (required) The data itself. The data can be either
a single or multi (as of 3.3) dimensional array.


Example 4.1
What we are doing:
Send user ID and ﬁrst name from PHP over to
custom.js and alert the user.
<?php

**/

add_action( 'wp_enqueue_scripts', 'send_user_data_to_custom' );
function send_user_data_to_custom() {
$data = array(
'userid' => $current_user->ID,
'fname' => $current_user->user_firstname
);
}
?>

wp_localize_script( 'custom-script', 'userinfo', $data );


Example 4.1
What we are doing:
Send user ID and ﬁrst name from PHP over to
custom.js and alert the user.
<?php

**/

add_action( 'wp_enqueue_scripts', 'send_user_data_to_custom' );
in JavaScript the data can be called by
function send_user_data_to_custom() {
userinfo.userid and userinfo.fname

using


+

$data = array(
'userid' => $current_user->ID,
'fname' => $current_user->user_firstname
);
}
?>

wp_localize_script( 'custom-script', 'userinfo', $data );


Example 4.1
JavaScript: custom.js
jQuery(document).ready(function($){
alert("Hey, " + userinfo.fname + ", your user ID is " + userinfo.userid + ". Boom!");
});


WCLV13 JavaScript

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