keypress事件是（在其原始IE中）表单，以及在Safari / Chrome中）关于添加到文本字段的实际字符。退格键显然不会在字段值中添加新字符，因此它不会导致按键事件。

The "keypress" event is (in its original IE form, and in Safari/Chrome) about an actual character being added to a text field. The backspace key clearly does not add a new character to the field value, so it causes no keypress event.

Firefox和Opera对于生成输入更加不知所措事件。

Firefox and Opera are a little more willy-nilly about generating typing events.

PPK（ quirksmode ）认为IE和Webkit行为是明智的行为，我非常同意。

PPK (quirksmode) considers the IE and Webkit behaviors to be the sensible ones, and I pretty much agree.