JavaScript and native DOM state
Inspect text insertion, event lifecycle, node movement and form values with fixed local programs.
Display a text value without parsing it as markup
Insert the supplied tag-looking string as text and count actual descendants.
Toggle one class without replacing the rest
Add one state token while keeping the existing class names.
Find the intended action when a nested element is clicked
Resolve a nested click to its action button within the delegated container.
Cancel a default without stopping event propagation
Read cancellation and propagation as two separate event flags.
Dispose a local listener with an abort signal
Remove a signal-scoped click listener between two fixed clicks.
Choose between a snapshot and a live DOM collection
Compare an old selector result with a collection that updates when nodes change.
Clone markup without assuming its listeners are cloned
Clone a button’s markup and identify the listener that remains with its original node.
Append a fragment and watch its children move
Insert a DocumentFragment and follow where its child nodes move.
Read data attributes as strings before interpreting them
Interpret fixed data attributes only after inspecting their string values.
Inspect which local form controls enter FormData
Inspect the initial local entry list, including repeated names and omitted controls.
Read an empty number input without inventing zero
Compare a number input’s raw text, valueAsNumber and Number conversion.