html change 事件

The change event is fired for <input>, <select>, and <textarea> elements when a change to the element's value is committed by the user. Unlike the inputevent, the change event is not necessarily fired for each change to an element's value.

事件在元素input,select,textarea的內容由用戶改變的時候觸發，而且不像input事件每一次的改變都觸發。

Description

Depending on the kind of form element being changed and the way the user interacts with the element, the change event fires at a different moment:

• When the element is activated (by clicking or using the keyboard) for <input type="radio"> and <input type="checkbox">;

• When the user commits the change explicitly (e.g. by selecting a value from a <select>'s dropdown with a mouse click, by selecting a date from a date picker for <input type="date">, by selecting a file in the file picker for <input type="file">, etc.);

• When the element loses focus after its value was changed, but not commited (e.g. after editing the value of <textarea> or <input type="text">).

Different browsers do not always agree whether a change event should be fired for certain types of interaction. For example, keyboard navigation in <select>elements never fires a change event in Gecko until the user hits Enter or switches the focus away from the <select> (see bug 126379).

描述

事件觸發依賴於元素類型，觸發方式以及觸發不一樣時刻，以下所示

• 對於<input type='radio'>和<input type="checkbox">，元素激活時觸發（經過點擊或者鍵盤）

• 用戶明確提交更改（例如，鼠標點擊選取select，從 <input type="date">選取日期，從<input type="file">選取文件）

• 元素失去焦點時內容以改變，但並未提交（例如 <textarea> 或者 <input type="text">）也會觸發、

不一樣的遊覽器不保證特定類型的交互觸發change事件。例如，在Gecko，除非用戶點擊enter或者從<select>移去焦點，經過鍵盤選取select將不會觸發change事件。




引用：https://developer.mozilla.org/en-US/docs/Web/Events/change

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怪不得不少change事件和預想的不同。