检测由标签键启动的焦点？ [英] Detect focus initiated by tab key?

问题描述

我想检测一个元素的焦点事件，但只有当用户按Tab键启动它时。例如：

I want to detect the focus event of an element, but only if it was initiated by the user pressing the tab key. For example:

<input type="text" id="foo" />
<input type="text" id="detect" />

如果用户专注于 #foo 并按 Tab ，我想要事件一旦 #detect 变得专注（或焦点事件中的条件为true）即可​​触发。相反，如果用户只需点击 #detect 字段来对焦，我不希望事件触发（或者我想要焦点事件调用中的条件为假）。

If the user is focused on #foo and presses Tab, I want the event to fire once #detect becomes focused (or a conditional inside the focus event to be true). Conversely, if the user simply clicks on the #detect field to focus it, I do not want the event to fire (or I want the conditional inside the focus event call to be false).

我不想使用 #foo 的keydown事件，并检查tab键是否按下，因为我想要的方法是独立于任何其他元素。

I don't want to use the keydown event of #foo and check if the tab key was pressed, as I want the approach to be independent of any other element.

我看过以下代码的控制台输出，但是没有注意到两者之间的真正差异聚焦方法：

I looked through the console output of the following code, but couldn't notice any real differences between the two methods of focusing:

$('#detect').on('focus', function(e){
   console.log(e); 
});

（小提琴< a>）

(fiddle)

这是否可以以相对简单的方式完成？

Is this possible to accomplish in a relatively simple way?

推荐答案

我知道您已经接受了一个答案，但您可以使用以下内容测试按下的按钮：

I know you have accepted an answer but you could test the button pressed using the following:

$('#detect').on('focus', function(e){
    $(window).keyup(function (e) {
        var code = (e.keyCode ? e.keyCode : e.which);
        if (code == 9) {
           alert('I was tabbed!');
        }
    });
});

http： //jsfiddle.net/LPGLm/1/

修改：更改收听者：

$(window).keyup(function (e) {
    var code = (e.keyCode ? e.keyCode : e.which);
    if (code == 9 && $('#detect:focus').length) {
        alert('I was tabbed!');
    }
});

http： //jsfiddle.net/LPGLm/7/

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