JavaScript defer checker
JavaScript defer checker lists script loading attributes from page HTML. Review defer and async values before testing script order and rendering behavior.
JavaScript defer checker: what this tool checks
JavaScript defer checker inventories script elements in a fetched page and labels their loading attributes. It shows external script addresses or identifies embedded scripts, helping developers review a template's script setup before investigating loading order, rendering delays, or a recent integration change.
How to use it
- Enter the complete URL of the page to inspect.
- Submit it and review the script total and non-deferred count.
- Compare the listed attribute labels with the original markup and test any proposed changes in the browser.
Understanding your results
The check uses attribute text values, so a valid bare Boolean attribute such as defer can be reported as absent when its value is empty. Async scripts also count as non-deferred in this implementation. Inline scripts and module behavior need separate interpretation; this is not a browser execution trace.
Frequently asked questions
Should every script receive defer?
No. Script dependencies, execution timing, inline code, and module loading can require different handling. Changing an attribute without testing can break menus, forms, tracking, or other interactions.
Does the reported count measure blocked rendering time?
No. It counts markup and classifies attribute values. Use browser performance tools to measure whether a specific script actually delays visible content or user interactions.
Continue your review
Review referenced asset totals with the HTTP requests checker, inspect server response timing through the TTFB checker, and reduce a source script using the JS minifier.
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