javascript - 在 keyup 上获取文本区域中的字符

Question

我想获取文本区域中的字符数。这需要在每次击键时更新。所以我使用了这个简单的函数:

$(document).on('keyup', 'textarea', function () {
    var count = $(this).val().length;
    console.log(count); 
});

现在的问题是，如果我尝试快速打字，计数会重复。我们可以在控制台中看到重复。这种重复背后的原因是什么？我该如何避免呢？ 这是一个 fiddle :https://jsfiddle.net/w6mzzfd8/

谢谢!

Answer 1

根据文档:

The keypress event is sent to an element when the browser registers keyboard input. This is similar to the keydown event, except in the case of key repeats. If the user presses and holds a key, a keydown event is triggered once, but separate keypress events are triggered for each inserted character. In addition, modifier keys (such as Shift) trigger keydown events but not keypress events.

解决方案:

使用 keydown 而不是 keyup

代码:

$(document).on('keydown', 'textarea', function () {
 var count = $(this).val().length;
 console.log(count); 
});

Working Demo