WebPeek brings the four panels you already know to Safari on iPhone and iPad. Turn it on once and every page gets a small floating button; tap it and the inspector slides up over the page you are already reading.
ELEMENTS
• Tap the picker, then tap anything on the page to select it
• A real DOM tree with syntax colouring and a breadcrumb
• Edit attributes, text and outerHTML; delete nodes — all applied live
• Matched CSS rules, every computed property, and a box-model diagram
CONSOLE
• Every console.* call captured from the very first line of the page
• Uncaught errors, unhandled rejections and CSP violations, with stack traces
• Expandable object trees — arrays, Maps, Sets, typed arrays, DOM nodes
• An input line for running expressions, with history…
From the developer’s store description.