Eliminating Parser-Blocking Resources

Are there parser-blocking resources that shouldn’t load on every page?

Parser-blocking resources are scripts or stylesheets that prevent the browser from rendering a page until they are fully loaded. These can significantly slow down your website, especially on eCommerce platforms like Shopify and WooCommerce. It’s crucial to identify and manage these resources to improve page load times and overall user experience.

Identifying Parser-Blocking Resources

To identify parser-blocking resources, you can use tools like Google PageSpeed Insights or the Network tab in Chrome DevTools. Look for scripts and stylesheets that are marked as render-blocking.

Managing Parser-Blocking Resources in Shopify

In Shopify, you can manage parser-blocking resources by:

  • Loading JavaScript files asynchronously using the async attribute.
  • Deferring JavaScript files using the defer attribute.
  • Inlining critical CSS and deferring non-critical CSS.

Managing Parser-Blocking Resources in WooCommerce

In WooCommerce, you can manage parser-blocking resources by:

  • Using plugins like Autoptimize or WP Rocket to optimize CSS and JavaScript delivery.
  • Manually adding the async or defer attributes to your script tags in your theme’s functions.php file.
function add_async_defer_attributes($tag, $handle) {
    if ('example-handle' !== $handle) {
        return $tag;
    return str_replace(' src', ' async="async" src', $tag);
add_filter('script_loader_tag', 'add_async_defer_attributes', 10, 2);


By identifying and managing parser-blocking resources, you can significantly improve the performance of your Shopify or WooCommerce store. This will lead to faster page load times, better user experience, and potentially higher conversion rates.

Leave a Comment