防止浏览器中的ctrl + z [英] Preventing ctrl+z in browser

问题描述

我使用下面的代码示例来禁用 ctrl + c 和 ctrl + v 并且它可以正常工作。我在浏览器中使用类似的机制来禁用 ctrl + z （撤消），但它不起作用。

I used the code sample below to disable ctrl + c and ctrl + v and it works. I used similar mechanics to disable ctrl + z (undo) in the browser but it doesn't work.

var ctrlDown = false;
var ctrlKey = 17, vKey = 86, cKey = 67, zKey = 90;

$('body').keydown(function(e) {
  if (e.keyCode == 17 || e.keyCode == 91) {
    ctrlDown = true;
  };
}).keyup(function(e) {
  if (e.keyCode == 17 || e.keyCode == 91) {
    ctrlDown = false;
  };
});

$("body").keydown(function(e){
  if ((ctrlDown && e.keyCode == zKey) || (ctrlDown && e.keyCode == vKey) || (ctrlDown && e.keyCode == cKey)) {
    e.preventDefault();
    return false;
  }
});

推荐答案

我可以从测试中看到你的if条件$（body）。keydown处理程序没有触发。虽然ctrlDown确实设置为 true ，但由于某种原因，您的一系列条件未触发。我不认为在全局范围内存储密钥代码和ctrl状态将是一个很好的方法。

I can see from testing that the if condition in your $("body").keydown handler isn't firing. While ctrlDown does get set to true, for some reason your series of conditions isn't firing. I don't think storing key codes and ctrl state in the global scope is going to be a great approach.

而不是单独的处理程序测试ctrl使用，它' d更容易在zkeydown处理程序中测试是否正在使用Ctrl（或Meta即命令，与Mac兼容）。 事件对象具有布尔属性 ctrlKey 和 metaKey 这样的场合。所以你的代码是：

Rather than a separate handler testing for ctrl usage, it'd be easier to test just within the "z" keydown handler for whether Ctrl (or Meta i.e. command, to be Mac-compatible as well) is being used. The event object has Boolean properties ctrlKey and metaKey for just such occasions. So your code would be:

$("body").keydown(function(e){
  var zKey = 90;
  if ((e.ctrlKey || e.metaKey) && e.keyCode == zKey) {
    e.preventDefault();
    return false;
  }
});

这仍然没有那么强大，因为你只想检查metaKey在Mac上并检查Linux / Windows上的ctrl来处理一些边缘情况，有人可能会按下Meta + Z（这在Windows中做了什么？），但它已经接近了。它适用于我的Mac。

This is still not quite as robust as it could be, since you'd want to only check metaKey on Mac and check ctrl on Linux/Windows to handle a few edge cases where someone might press "Meta + Z" (does that do anything in Windows?), but it's close. It works on my Mac.

谨慎 - &您可能已经考虑过这一点 - 禁用操作系统级别的键盘快捷键可能非常危险。它以糟糕的方式混淆了用户的期望。如果你在一个大型浏览器应用程序中重写类似的东西，那么这很有意义。小心！

A caution—& you've probably already considered this—that disabling OS-level keyboard shortcuts can be really dangerous. It messes with user expectations in a bad way. If you're overriding to do something similar in a big browser app, that makes perfect sense, though. Be careful!

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