reduce javascript execution time shopify

Shopify Discussion
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Topic summary

A user seeks help reducing JavaScript execution time on their Shopify store, sharing a performance screenshot that indicates issues.

Proposed Solution:
Another participant provides a Liquid code snippet that implements lazy-loading for third-party scripts. The approach includes:

  • Script Removal: Uses Liquid to strip specific URLs from content_for_header
  • Deferred Injection: Delays script loading until user interaction (click, scroll, or keydown events)
  • Implementation: Requires adding target URLs to the urls_to_remove array

Note: The code snippet appears partially corrupted or reversed in the second half, which may affect implementation. The technique aims to improve initial page load performance by deferring non-critical JavaScript execution until users actively engage with the page.

Status: Solution proposed but not yet confirmed as tested or effective.

Summarized with AI on November 3. AI used: claude-sonnet-4-5-20250929.
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reduce javascript execution time shopify

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Screenshot_3.png999×543 24.2 KB

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{% comment %} remove URLs from asyncLoad {% endcomment %}

{% assign urls_to_remove = ’
https:exampleUrl1.com,
https:exampleUrl2.com,
https:exampleUrl3.com,
’
| strip_newlines
| replace: ’ ', ‘’
| split: ‘,’
%}

{% for url in urls_to_remove %}
{% assign content_for_header = content_for_header | remove: url %}
{% endfor %}

{{ content_for_header }}

{% comment %} inject app scripts after user interaction {% endcomment %}

you can use this script and modify it.