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CoreBoost v3.3.9

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@github-actions github-actions released this 12 May 21:39
· 1 commit to main since this release
v3.3.9
88cc0ac

🔄 Reworked - cb-lcp Strategy: Preload-Only (Remove <img> Injection)

Root Cause Analysis

The <img> injection approach was based on a false premise. Elementor's video background
fallback image is applied as style="background: url(...) 50% 50%; background-size: cover;"
via server-side PHP (Group_Control_Background selectors). This means:

  1. The CSS background paints immediately without JS — it is not lazy-loaded or gated
    on Elementor adding .e-lazyloaded.
  2. The PSI "resource load delay" metric measures image discovery time, not paint-blocking
    JS. The browser only discovers CSS background-image URLs after downloading and parsing
    the stylesheet — this is what causes the delay.
  3. A <link rel="preload" fetchpriority="high"> in <head> is the direct and correct fix —
    the preload scanner finds it during initial HTML tokenisation, before any CSS is fetched.
  4. Injecting a <img> as a child of the Elementor section was fighting Elementor's flex
    layout unnecessarily, causing double-height sections on desktop and size/overlap issues
    on mobile, with no benefit to the LCP metric.

Changes

  • inject_lcp_foreground_image() (Resource_Remover): removed <img> construction and
    injection entirely. The function now only extracts the image URL (via the 4-level cascade)
    and emits a <link rel="preload" as="image" fetchpriority="high"> before </head>. The
    section's opening tag is returned unmodified. No DOM changes, no layout impact.
  • output_lcp_img_styles() (Hero_Optimizer): removed method and wp_head hook — no
    <img> element exists to style.
  • define_hooks(): removed output_lcp_img_styles registration.
  • get_foreground_conversion_css(): .cb-lcp-img block updated to note removal.

What Still Fires

  • preload_video_hero() at wp_head priority 1 (via both preload_method dispatch and the
    unconditional enable_lcp_foreground_injection guard added in v3.3.7) — reads
    _elementor_data from DB and emits the preload tag early.
  • Output-buffer preload fallback in inject_lcp_foreground_image() — covers cases where
    preload_video_hero() misses the URL (e.g. non-standard Elementor structures).

Files Modified

  • includes/public/class-resource-remover.php — inject_lcp_foreground_image() img injection removed
  • includes/public/class-hero-optimizer.php — output_lcp_img_styles() removed; define_hooks() updated
Assets 3
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