Backspace deletes whole words instead of single characters

Phenomenon

In Safari on macOS, pressing Backspace may delete entire words instead of single characters, especially when the caret is positioned at word boundaries or after spaces.

Reproduction example

1. Create a contenteditable div.
2. Type some text with multiple words, e.g., “Hello world example”.
3. Place the caret at the end of a word (after “world”).
4. Press Backspace.
5. Observe how much text is deleted.

Observed behavior

• In Safari on macOS, Backspace may delete entire words.
• The deletion granularity is inconsistent.
• Sometimes single characters are deleted, sometimes whole words.

Expected behavior

• Backspace should delete one character at a time by default.
• Word-level deletion should only occur with modifier keys (e.g., Option+Backspace).
• The behavior should be consistent and predictable.