Start Network recording with a mobile viewport

How to find desktop resources on mobile

Cold-load at a narrow viewport, find the invisible component in DOM and connect its requests to their initiators. Compare with desktop and verify the mobile alternative preserves the feature.

Comparing desktop and mobile Network requests for a hidden component — Enable emulation before navigation or the preload scanner may already start desktop requests.

Quick check

Open a clean DevTools window, enable mobile device mode before entering the URL, Disable cache and Preserve log.
Load the page and locate the visually absent desktop component through Elements or its known selector.
Filter its images, JS, CSS, iframe and XHR/fetch in Network; inspect the Initiator column.
Save request count and transferred bytes, then repeat a cold desktop load.
Test the mobile alternative, navigation, forms and direct links; rotate and resize the viewport.

Good result: true desktop-only resources are absent from a cold mobile load while the required meaning and action remain in a light alternative.

Issue levels

How to rate unnecessary mobile loading
Observation	Level	Action
No desktop resources and mobile feature preserved	No issue	Save HAR for both layouts
A tiny hidden decorative asset loads	Low	Compare savings and complexity
Invisible slider/widget loads large assets and JS	High	Separate resource and initialization
Optimization removes mobile content or action	Critical	Restore an accessible alternative

Technical hidden-element check

[...document.querySelectorAll('img, iframe, video, [hidden]')]
  .filter(el => getComputedStyle(el).display === 'none' || !el.getClientRects().length)
  .map(el => ({ tag: el.tagName, src: el.currentSrc || el.src, class: el.className }))

This lists hidden elements in the current DOM but does not prove a download or include backgrounds, removed nodes or JS/API work. Confirm every candidate in Network by URL and initiator.

False conclusions and scope

A modern browser may avoid loading an img inside known display:none, but verify the actual network rather than assume.
Responsive picture/srcset selects one suitable source; no desktop URL in Network is expected.
A shared JS file can contain desktop code without a separate request; Coverage/bundle analysis is an additional check.
Service worker, cache and resizing after load distort results.
One viewport does not represent every phone, orientation, DPR or accessibility zoom.

Automated pricing applies to the agreed component and templates on the service page. Use the step-by-step guide for repairs.

How to Find Desktop Resources on Mobile