Defer JavaScript

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Magento Defer JavaScript Extension by BSSCommerce helps to defer parsing of JavaScript for Magento sites to speed up quickly . Effectively improve loading time, engage more customers and your sale is on way to boost up!

  • Instantly and automatically defer parsing of Javascript for Magento
  • Defer parsing of Javascript for Magento till the last moment
  • Defer Iframes loading effectively
  • Improve page ranking with major search engines
  • Work perfectly with Full page cache
  • Magento 2 Defer JavaScript is available!

1.4.x.x, 1.5.x.x, 1.6.x.x, 1.7.x.x, 1.8.x.x, 1.9.x.x

1.12.x.x, 1.13.x.x, 1.14.x.x

Availability: In stock


1147 magento sales off

Along with Lazy Image Loader, Magento Defer JavaScript Extension is also a useful extension that speeds up Magento store performance by automatically putting JavaScript files to the end of the page after loading all HTML and CSS. 

Outstanding Features of Magento Defer JavaScript Extension: 

    • Automatically defer parsing of JavaScript for Magento sites 

magento defer javascript-after installing

  • Defer Iframes loading 

If your webpage has some embed code of other sites, it means that the browser has to load JavaScript files of these pages along with your site. This thing will cause defer score of your website decrease or the site does not perform fast enough for better customer experience. Therefore, using Magento Defer JavaScript will help you to defer these Iframes effectively by loading Iframes of these embed sites only when your site finishes loading completely.

  • Improve Magento sites ranking with major search engines

Site speed is also an important factor to influence your website’s ranking on Search Engine Result Pages. Therefore, with Magento Defer JavaScript extension, your site speed is improved and search engines will evaluate it more highly than other ones with slower speed.  

  • Dramatically improve execution and rendering time which helps engage more customers

By deferring parsing of Javascript for Magento sites or in the other hand, moving JavaScript files to the bottom after loading HTML and CSS, websites will load faster and effectively increase the JavaScript Effects that makes site look better. Therefore, customers are likely to have more interaction with Magento sites instead of leaving immediately a site with slow performance.

  • Fix all the problems with Full Page Cache module and it works perfectly with FPC module.

Why is Magento Defer JavaScript Extension your must-have extension?

  • Effective Magento site speed improvement

The fact that scripts must be downloaded, parsed, and executed before the browser can begin to render a web page causes much of delay in time to load the main page at the startup. That ugly truth can make your customers leave your site at their first visit as many studies have shown that users will not tolerate more than a 4 second load time.

Magento Defer Parsing of JavaScript is developed to solve out this issue. It allows optimizing your Magento store performance quickly and easily.

The below picture shows Page Speed Result of before installing Magento Defer JavaScript Extension.

Low loading speed before installing Magento Defer JaveScript

And look at how it changes after Magento Defer JavaScript Extension by BSSCommerce is installed.

Higher loading speed after installingMagento Defer JavaScript Extension

  • Defer parsing JavaScript for Magento until the last moment

Basically, Deferring means that the other HTML files and CSS is loaded first then parsing of JavaScript files is implemented after all. This has no effect on the performance or usability of your web page, it merely rearranges the loading process so that JavaScript is deferred until the last possible moment - the outcome of this process is that your Magento page appears much quicker after defer parsing of JavaScript.

  • Easy configuration from backend

With a few clicks, you can get this extension work on your online store for better speed performance. Magento Defer JavaScript Extension by BSSCommerce is developed by our certificated developers who ensure that it’s well-compatible with default Magento and hardly find any conflicts.

User Guide

Click here to check out BSSCommerce's best extensions for your Magento store. We will help you to boost both your website's performance and sales.

Version 1.0.4:

  • Fix bugs for configuring with Full Page Cache module
  • Document update: How to fix BSS Defer Javascript for other Full Page Cache modules
  • Version 1.0.5:

  • Fix bugs for configuring with Full Page Cache module
  • Version 1.0.6:

  • Fix bugs when working with Full Page Cache module
  • Version 1.0.8:

  • Option to not defer selected script
  • Version 1.0.9:


    Version 1.1.1:

    Version 1.1.2: Defer iframe

    * Required Fields



    User Guide - Magento Defer JavaScript
    30-Day Money Back
    Free 1-Year Support
    Free Lifetime Update
    Free Installation


      • Best Defer JavaScript for Magento sites
        Thank to Defer Javascript extension, I can slove slow speed problem of my website.
        It was so slow and made customers to leave site immediately.
        I choose your extension because it is simple but effective quickly. and so amazing it improve my site so much.
        Love it!

        30 May 2017

        Mandel Marleau
      • Developer
        Deferring js and css is important so that your pages' content is toward the top of your page. Reason: Search Engine crawlers like Googlebot and Bingbot can get to a page's readable content without having to parse through lines and lines of scripts and style sheets.

        BSS Defer Javascript does exactly that. And it does it well, a.k.a eloquently.

        17 December 2016

        David Radovanovic
      • great extension
        it works great!! very good job BSS!!

        10 October 2016

      • Very good extension and great support!
        This module helped me a lot for my Google Page Speed score. Defering Js is essential and this module handeled it just fine. I had some problems after installing, as the compatability with the Lesti FPC was not 100%. However, the senior and founder of the bizz helped me and came up with a solution very swiftly. I highly recommend anyone to use this module. Thnx Trung!

        From Magento Connect on May 11, 2015

        07 March 2016

      • Great extension to improve Magento speed
        "This extension fixed my Defer JavaScript issue of my Magento store.
        I faced few problem after install but their support helped me to resolve those issues. Great support!"

        From Magento Connect on June 26, 2015

        07 March 2016

      • Great product
        "Great product by a great company!
        Does exactly what you want!"

        From Magento Connect on June 26, 2015

        07 March 2016

      • Good extension, even better support!
        Thanks to BSSCommerce we can get our GTMetrix / Google Pagespeed rating to a higher level. Support is superb, although they need to do some tweaking in extension files.

        From Magento Connect on August 20, 2015

        07 March 2016

      • Awsome Support / Extension
        "This worked great to take our site from 0/100 to 100/100 in Yslow and Gmetrix. BSS helped resolve the installation with great enthusiasm"

        From Magento Connect on September 24, 2015

        07 March 2016

      • Does exactly what its supposed to!
        "I had this extension installed in our store. Basically based on the information from GTMetrix, that our site speed can be faster if using Defer Javascript. Bsscommerce installed the extension for me at no additional cost, went really fast and smooth and does exactly what its supposed to. Rating on GTMetrix has improved and also the actuall speed is faster after carefully monitoring the difference!
        I would also recommend letting Bsscommerce help with the installation, as I know that defer javascript can be a bit tricky.
        Thank you very much for a great extension and awesome support!"

        From Magento Connect on January 8, 2016

        07 March 2016

      • A must for all Magento website
        "As most of us I needed a way to speed up my magento website.
        Being on a shared hosting the scenario was pretty scared, but after a mail with the developer I follow his suggestion and installed both the defer js and the bss FPC.
        The results are amazing!
        I went from 11 sec. to 4 sec. ( using gtmetrix) on my Magento website.
        I had few minor issues related to custom template but the developer help me in no time.
        Strongly suggested both for the support and for the funtionality."

        From Magento Connect on January 27, 2016

        07 March 2016

      • Best way to defer parsing of javascript in Magento!
        "After speeding up our website through the help of GTMetrix the only thing left was the message to 'defer parsing of javascript'. We looked through tutorials to do it ourselfs but without success. After searching for a while I came across this extension and decided to give it a try. It worked out of the box, even though some strange things were happening that later on could be addressed to a totally different change we made. The support team helped us find the problem even though it had nothing to do with their extension so we know they give great support as well!"

        From Magento Connect on February 5, 2016

        07 March 2016

      • Great extension
        "This extension sorted out our defer javascript problems we had when testing with webmaster tools and the likes.
        0 problems and worked right away."

        From Magento Connect on February 5, 2016

        07 March 2016

      • Simple the best
        "We have been searching a solution for the defer javascript on internet like anything. Defer Parsing was the main issue in the overall speed of our website but our search came to an end when we see this extension. We immediately contact the support and support was so helpful in helping us decide to buy this extension.
        Overall, a very pleasant experience."

        From Magento Connect on February 5, 2016

        07 March 2016

      • Best support, extension, everything
        An amazing module, my total sales increases sharply! Thank you very much for this helpful support and unbelievable innovation! Good luck!

        04 January 2016

      • Awsome!
        I have been absent for some time, but now I remember why I used to love this website. Thanks, I'll try and check back more often.

        19 November 2015

      • It's so great to see your site is working on smoothy
        "I was very impressed on how Defer Javascript can improve my site speed.
        It's so great to see my site is working on smoothy. Highly recommend!"

        06 August 2015

      • Satisfied with the quality and price
        I was trying to find a solution to the magento cache for a long time, tried modules for varnish and for memcached
        and I still had no best answer for speed loading solution until finding out Defer JavaScript. It works very well as described and I am satisfied with the price.

        09 June 2015

      • Satisfied with the quality and price
        "I was trying to find a solution to the magento cache for a long time, tried modules for varnish and for memcached
        and I still had no best answer for speed loading solution until finding out Defer JavaScript. It works very well as described and I am satisfied with the price."

        03 April 2015

      • Clean code and many features
        "I've tried many combinations to improve Magento performance, this module beats all.
        Clean code, many features and good support!"

        25 March 2015

      • I'm waiting for BSS new modules
        I bought 3 extensions from BSS. I always received very reasonable price with the best support ever. They also update new solutions for online store. I'm waiting for your new modules

        23 March 2015

      • Walter
        I have to say that Defer JavaScript is better than other more expensive solutions.
        I'm amazed at how it works and returns it brings back. Very useful extension!

        12 March 2015

        Awesome extension!
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