javascript - !variable 在 javascript 中不起作用

Question

我有一个带有代码的javascript:书签

javascript:document.body.contentEditable = !document.body.contentEditable; 

它应该打开和关闭页面的“编辑器”(仅用于对 friend 的恶作剧等)。但它没有达到预期的结果，当我点击书签时没有任何反应。打开 Javascript 控制台，我看到:

document.body.contentEditable
  "false"
!document.body.contentEditable
  false

以前，我使用了 javascript:document.body.contentEditable = true; 这使得页面可编辑，但我无法将其关闭。

Answer 1

您可能在 JavaScript 控制台中注意到，document.body.contentEditable 是一个字符串，而不是 bool 值。您可以这样做:

document.body.contentEditable = !(document.body.contentEditable == "true");

或者只是

document.body.contentEditable = document.body.contentEditable != "true";

The HTMLElement.contentEditable property is used to indicate whether or not the element is editable. This enumerated attribute can have the following values:

• "true" indicates that the element is contenteditable.
• "false" indicates that the element cannot be edited.
• "inherit" indicates that the element inherits its parent's editable status.

https://developer.mozilla.org/en/docs/Web/API/HTMLElement/contentEditable