Baseline typing and composition in a simple contenteditable region
OS: Any Any · Device: Desktop or Laptop Any · Browser: Chrome Latest · Keyboard: US
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This case describes a baseline scenario for inspecting how a plain `contenteditable` region behaves
This case describes a baseline scenario for inspecting how a plain contenteditable region behaves
with typing, composition, and basic navigation keys.
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| Case | OS | Device | Browser | Keyboard | Status |
|---|---|---|---|---|---|
| example-baseline | Any Any | Desktop or Laptop Any | Chrome Latest | US | draft |
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OS: Any Any · Device: Desktop or Laptop Any · Browser: Chrome Latest · Keyboard: US
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During IME composition or in certain browser/IME combinations, the beforeinput event may have a different inputType than the corresponding input event. For example, beforeinput may fire with insertCompositionText while input fires with deleteContentBackward. This mismatch can cause handlers to misinterpret the actual DOM change and requires storing beforeinput's targetRanges for use in input event handling.
The selection (window.getSelection()) in beforeinput events can differ from the selection in corresponding input events. This mismatch can occur during IME composition, text prediction, or when typing adjacent to formatted elements like links. The selection in beforeinput may include adjacent formatted text, while input selection reflects the final cursor position.
Analysis of how out-of-order or missing composition events disrupt editor state synchronization.
The getTargetRanges() method in beforeinput events may return an empty array or undefined in various scenarios, including text prediction, certain IME compositions, or specific browser/device combinations. When getTargetRanges() is unavailable, developers must rely on window.getSelection() as a fallback, but this may be less accurate.
When using IME to input CJK text in heading elements (H1, H2, etc.) in WebKit browsers, pressing Space to confirm composition causes both the raw Pinyin buffer AND the confirmed characters to appear together.
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