textselection

Textselection refers to the action of marking a portion of text within a document or user interface. The selected text is typically highlighted to indicate that it can be operated on, such as being copied, cut, pasted, deleted, or reformatted. In many environments, the selection is visually represented by a highlighted region and, when applicable, an insertion caret indicating the start or end of the selection.

Users create selections through a combination of input methods. Common interactions include dragging the mouse over text, using keyboard shortcuts such as shift with arrow keys, or clicking to set a new anchor point and then extending the selection. On touch devices, tapping and dragging selects text, while double-clicking or triple-clicking can select a word or a line, respectively. Some editors also support rectangular or column selections for selecting blocks of text across multiple lines.

Internally, a selection is usually described by a start and end position within the text, or by an anchor and a caret. Web browsers expose this through the Selection and Range APIs, which track the current user selection within the document and update as the user interacts with contenteditable regions or forms. Applications may abstract these concepts differently, but the core idea remains: a defined substring or region that can be manipulated as a unit.

Challenges and accessibility considerations include handling complex text layouts, such as grapheme clusters and bidirectional scripts, which can affect boundary accuracy. Screen readers and other assistive technologies rely on clear, predictable selection behavior to convey context to users navigating with keyboards or touch.