尝试找出jQuery中是否有错误或我在做什么

Question

$(document).keydown(function (event)
    {
    alert(event.which);
    });

For the semicolon key, ; , this gives 59 in Firefox and 186 in Chrome. However, from the jQuery reference page for the keydown event, it says

"While browsers use differing properties to store this information, jQuery normalizes the .which property so you can reliably use it to retrieve the key code. This code corresponds to a key on the keyboard, including codes for special keys such as arrows."

Am I missing something?

Answer 1

The which property is a "one stop shop" for which key was pressed, allowing you to ignore the differences between the keyCode and charCode properties. That is the "normalization" that jQuery provides.

The difference in the value of which comes down to a difference between the way the various browsers supply the information - so you'll have to write code to handle the different values that come back. There are a few references to this behavior online.

Answer 2

A quick Google search says you will simply have to test for both. This is a consistent inconsistency with Firefox.

Answer 3

我不了解jQuery，但建议您坚持按keypress事件来键入键，而仅对诸如箭头之类的特殊键使用keydown事件。

Answer 4

Here is the entirety of the "normalization" that jQuery does:

if ( event.which == null ) {
    event.which = original.charCode != null ? original.charCode : original.keyCode;
}

Looks like it just gets keyCode if charCode doesn't exist. And charCode is only used if event.which doesn't already exist. It doesn't change the numbers around to make them consistent.