QueueForge – Interaction to Next Paint Fixer

Google's Core Web Vitals now use Interaction to Next Paint (INP) instead of First Input Delay. Caching plugins make pages load fast, but they do nothing about the bloated JavaScript from other plugins, themes, ads, and analytics that blocks the browser's main thread and makes mobile interactions feel choppy. QueueForge INP Fixer attacks INP directly:

• Delays eligible JavaScript until the visitor's first scroll, tap, key press, or mouse move. The main thread stays free during the critical early window, so the page responds immediately.
• Yields the main thread between scripts when the deferred code finally runs, using the native scheduler.yield() (with a setTimeout fallback) so the queued scripts do not re-block the thread in one long task.
• Fallback timeout loads delayed scripts automatically after N seconds even with no interaction, protecting analytics and ad impressions.
• Live INP overlay for admins shows measured INP and long-task blocking time right on the front end, using PerformanceObserver (event + longtask).

Key Features

• Delay all eligible third-party / theme JavaScript until first interaction
• Main-thread yielding between deferred scripts (scheduler.yield() + fallback)
• Configurable fallback timeout (0 = interaction only)
• Optional jQuery delay (off by default for safety)
• Keyword exclusion list, plus per-tag data-no-optimize opt-out
• Skips logged-in editors so page builders keep working
• Live INP + blocking-time debug overlay (admins only)
• ?queueforge_off URL switch to bypass the delay for one page load
• No database writes on the front end; nothing is cached or stored per visitor

Why INP? INP measures how quickly the page visually responds to every interaction across the whole visit, not just the first one. The single biggest cause of poor INP is JavaScript executing long tasks on the main thread while the user is trying to interact. Delaying that JavaScript until it is actually needed — and breaking its execution into yield-separated chunks — is the most direct fix. Developer-Friendly

• qfinp_exclusions filter to programmatically add never-delay keywords.
• Uses an output buffer on template_redirect; no edits to your theme or other plugins.

1.1.0

• Fix: delayed scripts never actually ran. The plugin parked its own configuration object alongside everything else, because WordPress names that tag after the script handle (qfinp-runtime-js-before) and the exclusion list only looked for queueforge. The runtime booted with an empty config, bound no interaction listeners, set no fallback timer, and restored nothing — so on every site running 1.0.0, delayed scripts stayed dead for the life of the page. The default "skip logged-in editors" setting is why this went unnoticed: signed in, you never saw the optimised page.
• Fix: a large inline script could blank the whole page. Past PCRE's backtrack limit the rewrite returned null, and returning null from an output-buffer handler makes PHP emit an empty response. Roughly 1 MB of inline JavaScript was enough, which page builders produce routinely. The original HTML is now returned untouched instead.
• Change: delay is switched off on upgrade. Because the optimisation never ran in 1.0.0, no existing site has ever experienced it. Enabling it automatically would have been shipping brand-new behaviour to every install at once, so upgrades now start with it off and an admin notice explaining why. Fresh installs are unaffected.
• Fix: the debug overlay could show to visitors. Config was passed through wp_localize_script, which casts every value to a string — so 0 arrived as "0", which is truthy in JavaScript. Now sent as real JSON via wp_add_inline_script.
• New: re-firing DOMContentLoaded/load is now opt-in and off by default. Those are global events, so re-dispatching them also re-runs handlers from scripts that were never delayed, double-counting analytics and initialising sliders twice. The namespaced queueforge-scripts-loaded event is always emitted.
• Fix: scripts marked async no longer block the restore queue, preserving the parallel fetching those tags asked for.
• Fix: added a capability check to the notice-dismiss handler, and stopped the support notice marking itself dismissed simply by rendering.

1.0.0

• Initial release: interaction-delayed JavaScript, main-thread yielding, fallback timeout, exclusions, logged-in skip, and live INP/long-task overlay.
• All output is escaped late, including the admin-notice nonce passed to inline JavaScript via wp_json_encode().
• Every function, option, and the localized config object uses the qfinp prefix to avoid conflicts with other plugins.