The State of Web Vitals

Script initiators and the Core Web Vitals

97.7% of audited sites (192,444) load scripts directly from the HTML parser (95% good INP, 86ms median), while 75.0% inject scripts via other scripts (95% good INP, 88ms median) and 18.2% trigger scripts from other initiators (93% good INP).

Field data PhoneDesktopAll Scope All sites October 2026 edition · All devices field outcomes
INP Interaction LCP Loading

75.0% of sites use script-injected scripts script initiator type, and 95% of those sites have a good INP, against 95% of all sites.

The State of Web Vitals · October 2026 · 210,902 crawled sites · 196,263 with all devices field data · 196,999 sites with script initiator typeBy Arjen Karel · corewebvitals.io/state-of-cwv
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Core Web Vitals pass rate

Sites with script-injected scripts script initiator type have a good INP most often: 95%, against 95% of all sites. Sites with other script initiators script initiators have it least often, at 93%.

SitesGood, needs improvement, poor INPMedian
All sites196,26395%87ms
Script-injected (tag managers / loaders) 75.0%142,70495%88ms
Inline <script> execution 96.5%182,90695%87ms
HTML parser (<script src>) 97.7%185,24795%86ms
Other initiators (workers / preloads) 18.2%34,52293%89ms
GoodNeeds improvementPoorSites: with Chrome field data
The State of Web Vitals · October 2026 · 210,902 crawled sites · 196,263 with all devices field data · 196,999 sites with script initiator typeBy Arjen Karel · corewebvitals.io/state-of-cwv
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Script initiator type usage

Parser-initiated scripts is the most used: 97.7% of sites. Script-injected scripts is 75.0% of sites.

Sites using each option (sites can use more than one) 196,999 sites
HTML parser (<script src>) 97.7% Inline <script> execution 96.5% Script-injected (tag managers / loaders) 75.0%
HTML parser (<script src>) 97.7% Inline <script> execution 96.5% Script-injected (tag managers / loaders) 75.0% Other initiators (workers / preloads) 18.2%
The State of Web Vitals · October 2026 · 210,902 crawled sites · 196,263 with all devices field data · 196,999 sites with script initiator typeBy Arjen Karel · corewebvitals.io/state-of-cwv
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Understanding script initiators

Parser-discovered scripts versus cascading script-injected chains

When scripts are declared in HTML (97.7% of sites, 192,444), the browser preload scanner discovers them immediately (95% good INP, 86ms median). On 75.0% of sites (147,825), scripts are dynamically injected by other scripts such as Google Tag Manager or loader snippets (95% good INP, 88ms median), while 18.2% (35,826) trigger scripts via other initiators (93% good INP, 89ms median).

Prefer declarative <script defer> tags in HTML over JavaScript loader chains that inject second- and third-level scripts at runtime, and throttle tag-manager injection so late scripts do not fire during user input. Across all audited sites, 97.7% use parser-initiated scripts (95% good INP) and 75.0% use script-injected loaders (95% good INP).

Go fix it Avoid chaining critical requests → The case for limiting analytics and tracking scripts → Head vs footer JavaScript →
The State of Web Vitals · October 2026 · 210,902 crawled sites · 196,263 with all devices field data · 196,999 sites with script initiator typeBy Arjen Karel · corewebvitals.io/state-of-cwv
Platform & Framework Takeaways

How script initiator type plays out per platform

What the field data shows when you isolate a single CMS or framework.

WordPress 65,494 sites
98% vs 97% good INP (parser-initiated vs other initiators)

87.1% of WordPress sites load script-injected scripts, while 10.4% with other initiators pass INP at 97%.

Across 65,494 WordPress sites, 98.7% load scripts from the HTML parser (98% good INP, 86ms median), 87.1% inject scripts from other scripts (98% good INP), and 10.4% use other initiators (97% good INP, 88ms median).

Read the WordPress script initiator breakdown →
Shopify 8,570 stores
96% vs 94% good INP (parser-initiated vs other initiators)

99.9% of Shopify stores use script-injected loaders, while 19.1% with other initiators pass INP at 94%.

Across Shopify storefronts, 99.8% load parser-initiated scripts (96% good INP), 99.9% load script-initiated scripts (96% good INP, 97ms median), and 19.1% have other script initiators (94% good INP, 104ms median).

Read the Shopify script initiator breakdown →
React & Next.js 9,570 sites
99.6% / 95.1% parser / script-injected on React

99.6% of React & Next.js sites declare scripts in HTML and 95.1% also load script-initiated chunks (95% good INP).

Across 9,570 React sites, 99.6% use parser-discovered <script> tags (95% good INP), 95.1% load script-initiated chunks (95% good INP), and 71.6% use other initiators (95% good INP).

Related signals Uses @import → Iframe dimensions set → Responsive image markup → Third-party share → By Arjen Karel · 210,902 crawled sites (196,263 with all devices Chrome field data, 196,999 sites with script initiator type, October 2026) · How we measured