Tip: More information about javascript optimization can be found in this blog by Ilya Grigorik, web performance engineer at Google and author of the O'Reilly book High Performance Browser Networking (free online).

Optimize Javascript Loading

onchange="if (jQuery(this).is(':checked')) { jQuery('.jsdeliveryoptions').show(); } else { jQuery('.jsdeliveryoptions').hide(); }"> Enabled

When enabled, Javascript files are loaded asynchronously using an enhanced version of little-loader from Walmart Labs (reference).

Javascript Load Optimization

Warning: It may require some tweaking of the settings to prevent javascript problems.

Script Loader	> little-loader from Walmart Labs (reference) A stable async script loader that works in old browsers. > little-loader + HTML5 Web Worker and Fetch API based script loader with localStorage cache This script loader requires the Javascript proxy to be enabled to bypass CORS. A state of the art script loader for optimal mobile speed, inspired by basket.js (by a Google engineer), a script loading concept in use by Google. With fallback to little-loader for old browsers. Advantages of the HTML5 script loader ➤ 0 javascript file download during navigation ➤ 0 javascript file download for returning visitors ➤ abide WordPress dependencies ➤ faster script loading than browser cache, especially on mobile
Position	Select the position where the async loading of Javascript will start.
Ignore List	<?php if (isset($options['jsdelivery_ignore'])) { echo $this->CTRL->admin->newline_array_string($options['jsdelivery_ignore']); } ?> Scripts to ignore in Javascript delivery optimization. One script per line. The files will be left untouched in the HTML.
Remove List	<?php if (isset($options['jsdelivery_remove'])) { echo $this->CTRL->admin->newline_array_string($options['jsdelivery_remove']); } ?> Scripts to remove from HTML. One script per line. This feature enables to include small plugin related scripts inline.
Force Async	onchange="if (!jQuery(this).is(':checked')) { jQuery('.jsdelivery_async_no_options').show(); } else { jQuery('.jsdelivery_async_no_options').hide(); }"> Enabled When enabled, all scripts are loaded asynchronously.
Async Force List	<?php if (isset($options['jsdelivery_async'])) { echo $this->CTRL->admin->newline_array_string($options['jsdelivery_async']); } ?> Enter (parts of) scripts to force to load async. All other scripts are loaded in sequential blocking order if not specifically configured as async in HTML. Example: Script1: non-async [wait...] Script 2,3,4: async, Script 5: non-async [wait...] Script 6
Async Disabled List	<?php if (isset($options['jsdelivery_async_disabled'])) { echo $this->CTRL->admin->newline_array_string($options['jsdelivery_async_disabled']); } ?> Enter (parts of) scripts to force to load blocking (non-async).
requestIdleCallback	This feature requires the HTML5 script loader. This feature only applies to localStorage cached scripts. Our new plugin will enable this option for all scripts. ><?php if (isset($options['jsdelivery_idle'])) { echo $this->CTRL->admin->newline_array_string($options['jsdelivery_idle']); } ?> Enter a list with `script_string[:timeout_ms]` entries (one per line) to execute scripts in CPU idle time within an optional timeout in milliseconds. This feature enables to prioritize script execution. (more information) Example: `script.js:2000` (script.js should execute when CPU is available or within 2 seconds). Timeout is optional.
Abide Dependencies	> Enabled When enabled, scripts will be loaded in sequential order abiding the WordPress dependency configuration from wp_enqueue_script().
jQuery Stub	> Enabled When enabled, a queue captures basic jQuery functionality such as `jQuery(function($){ ... });` and `$(document).bind('ready')` in inline scripts. This feature enables to load jQuery async.

Lazy Load Scripts

onchange="if (jQuery(this).is(':checked')) { jQuery('.lazyscriptsoptions').show(); } else { jQuery('.lazyscriptsoptions').hide(); }"> Enabled

When enabled, the widget module from jQuery Lazy Load XT is loaded to enable lazy loading of inline scripts such as Facebook like and Twitter follow buttons.

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