Initial focus

When a dialog opens, something gets focus. If you did not choose, the choice was made for you: focus stays on the body, and the reader tabs from the top of the page into a dialog they are already looking at, or a naive implementation grabs the first tabbable element, which in most dialog layouts is the close button in the corner. Initial focus is the decision itself, made once per surface.

The answer depends on what the surface is for. A dialog whose job is input gets the first field, so the reader can start typing. A confirmation gets the safest action, which for a destructive confirmation means Cancel and never Delete: the reader may press Enter before they have read anything, and initial focus decides what that press does. A dialog with no obvious first control, or one whose title carries the important information, gets the container instead, which needs tabindex="-1" and gives assistive technology the whole thing to read from the top. A long non-interactive surface is the same case. The one answer that is never right is whatever happened to come first in the markup.

The HTML autofocus attribute expresses this declaratively and is fine inside a dialog that has just opened, since it fires when the dialog is shown. On a page load it is a different proposition: focus jumps past everything above the field, the reader loses the page’s beginning, and on small screens the keyboard opens uninvited. A search-first page can earn it. A newsletter box cannot.

Its neighbours divide cleanly, one sentence each. Focus management is the whole practice of deciding where focus goes at every change, and initial focus is its first decision. Focus trap is what keeps focus inside the surface after it has landed. Focus order is the sequence Tab follows from that landing point onward. Focus visible is whether the ring gets drawn where focus arrives, which matters here because a landing nobody can see is indistinguishable from no landing at all.