The State of Web Vitals

Script initiators on React sites

99.6% of audited sites (9,536) load scripts directly from the HTML parser (92% good INP, 90ms median), while 95.1% inject scripts via other scripts (93% good INP, 90ms median) and 71.6% trigger scripts from other initiators (93% good INP).

Field data PhoneDesktopAll Scope All sites October 2026 edition · Phone field outcomes · React sites only
React Scoped to 9,570 sites out of 210,902 analyzed (frameworks) Compare with all sites →
INP Interaction LCP Loading

95.1% of React sites use script-injected scripts script initiator type, and 93% of those sites have a good INP, against 92% of all React sites.

The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy 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: 93%, against 92% of all React sites. Sites with parser-initiated scripts script initiators have it least often, at 92%.

SitesGood, needs improvement, poor INPMedian
All React sites5,48892%90ms
Script-injected (tag managers / loaders) 95.1%5,21393%90ms
Inline <script> execution 99.6%5,45993%90ms
Other initiators (workers / preloads) 71.6%3,84093%84ms
HTML parser (<script src>) 99.6%5,46692%90ms
GoodNeeds improvementPoorSites: with Chrome field data
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
2

Script initiator type usage

Parser-initiated scripts is the most used: 99.6% of React sites. Script-injected scripts is 95.1% of React sites.

Sites using each option (sites can use more than one) 9,570 sites
HTML parser (<script src>) 99.6% Inline <script> execution 99.6% Script-injected (tag managers / loaders) 95.1% Other initiators (workers / preloads) 71.6%
HTML parser (<script src>) 99.6% Inline <script> execution 99.6% Script-injected (tag managers / loaders) 95.1% Other initiators (workers / preloads) 71.6%
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
3

Script initiator type per platform

Wix sets the script initiator type to script-injected scripts on 100% of its sites, and 96% of Wix sites have a good INP, against 92% of all sites. WordPress sets the script initiator type to inline scripts on 100% of its sites, and 96% of WordPress sites have a good INP.

PlatformScript initiator type on its sitesGood INP
All React sites 9,570 sitesHTML parser (<script src>) 100%Inline <script> execution 100%Script-injected (tag managers / loaders) 95%Other initiators (workers / preloads) 72%92%
Wix 5,824 sitesHTML parser (<script src>) 100%Other initiators (workers / preloads) 100%Inline <script> execution 100%Script-injected (tag managers / loaders) 100%96%
WordPress 2,342 sitesInline <script> execution 100%HTML parser (<script src>) 99%Script-injected (tag managers / loaders) 88%Other initiators (workers / preloads) 13%96%
HTML parser (<script src>) Inline <script> execution Script-injected (tag managers / loaders) Other initiators (workers / preloads)
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
4

Script initiator or the platform

Does the platform explain the script initiator type difference?

On Wix, 96% of sites with script-injected scripts script initiator type have a good INP, against 96% of Wix sites with parser-initiated scripts. Within Wix, sites with script-injected scripts and parser-initiated scripts have a good INP about equally often. On WordPress, 96% of sites with script-injected scripts script initiator type have a good INP, against 96% of WordPress sites with parser-initiated scripts. Within WordPress, sites with script-injected scripts and parser-initiated scripts have a good INP about equally often.

Parser-discovered scripts versus cascading script-injected chains

When scripts are declared in HTML (99.6% of sites, 9,536), the browser preload scanner discovers them immediately (92% good INP, 90ms median). On 95.1% of sites (9,098), scripts are dynamically injected by other scripts such as Google Tag Manager or loader snippets (93% good INP, 90ms median), while 71.6% (6,853) trigger scripts via other initiators (93% good INP, 84ms median).

The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
5

Understanding script initiators

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, 99.6% use parser-initiated scripts (92% good INP) and 95.1% use script-injected loaders (93% 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 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
Related signals Uses @import → Iframe dimensions set → Responsive image markup → Third-party share → By Arjen Karel · 9,570 crawled React sites (5,488 with phone Chrome field data, October 2026) · How we measured