Title: Defer Non-Essential JavaScript
Last modified: January 23, 2023

---

# Defer Non-Essential JavaScript

 *  Resolved [Thomas](https://wordpress.org/support/users/thehinesgaphideaway/)
 * (@thehinesgaphideaway)
 * [3 years, 3 months ago](https://wordpress.org/support/topic/defer-non-essential-javascript/)
 * When Jetpack Boost’s Defer Non-Essential JavaScript is enabled, it causes the
   ical generation on this theme to fail. I have contacted the rentals developer
   which state they cannot help because the offending plugin (boost) breaks their
   functionality and boost must address it. For now, I am forced to disable Defer
   Non-Essential JavaScript which helps our site gain much needed performance.
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fdefer-non-essential-javascript%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 4 replies - 1 through 4 (of 4 total)

 *  [Daniel](https://wordpress.org/support/users/ihenetudan/)
 * (@ihenetudan)
 * [3 years, 3 months ago](https://wordpress.org/support/topic/defer-non-essential-javascript/#post-16400454)
 * Hi there,
 * If the Jetpack Boost plugin’s “Defer Non-Essential JavaScript” option is causing
   the ical generation on your theme to fail, it is likely that the theme’s ical
   generation code is not compatible with the way Jetpack Boost is deferring non-
   essential JavaScript.
 * If the developer can share more information about this incompatibility, that 
   could help inform how we improve the Boost feature.
 * Note that disabling the “Defer Non-Essential JavaScript” option in Jetpack Boost
   will allow the ical generation to work properly, but it will also decrease the
   performance benefits gained from using Boost.
 *  Thread Starter [Thomas](https://wordpress.org/support/users/thehinesgaphideaway/)
 * (@thehinesgaphideaway)
 * [3 years, 3 months ago](https://wordpress.org/support/topic/defer-non-essential-javascript/#post-16400502)
 * Thanks for the response; I will copy this to the developer so they can help further.
 *  Thread Starter [Thomas](https://wordpress.org/support/users/thehinesgaphideaway/)
 * (@thehinesgaphideaway)
 * [3 years, 3 months ago](https://wordpress.org/support/topic/defer-non-essential-javascript/#post-16404024)
 * Hi, the theme developer has indicated:
 * “Usually, we recommend NOT enabling options like combine, minify js or CSS.  
   Since you have 3rd party plugin included in the theme, such an option might make
   more harm, than help with speed.”
 * However, I disagree, as the choice to use plugins is our own and I feel boost
   is helpful. The theme also breaks functionality with WP Fastest Cache.
 * I think I’ll look into the theme code to see how it works and perform changes/
   testing myself and get back to you when I have information to share, if able.
 * Thanks!
 *  Plugin Support [Dan (a11n)](https://wordpress.org/support/users/drawmyface/)
 * (@drawmyface)
 * [3 years, 3 months ago](https://wordpress.org/support/topic/defer-non-essential-javascript/#post-16407316)
 * Sounds good, please let us know what you find.

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘Defer Non-Essential JavaScript’ is closed to new replies.

 * ![](https://ps.w.org/jetpack-boost/assets/icon.svg?rev=2818794)
 * [Jetpack Boost - Website Speed, Performance and Critical CSS](https://wordpress.org/plugins/jetpack-boost/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/jetpack-boost/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/jetpack-boost/)
 * [Active Topics](https://wordpress.org/support/plugin/jetpack-boost/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/jetpack-boost/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/jetpack-boost/reviews/)

 * 4 replies
 * 3 participants
 * Last reply from: [Dan (a11n)](https://wordpress.org/support/users/drawmyface/)
 * Last activity: [3 years, 3 months ago](https://wordpress.org/support/topic/defer-non-essential-javascript/#post-16407316)
 * Status: resolved