我遇到过一个要求，即在显示实际警报消息的同时显示默认消息。这就是我如何做到的。

    const actualAlertFunc = window.alert;
    window.alert = function(msg) {
         actualAlertFunc('some default message '+ msg);
    }

我已经在chrome上测试过了。 我不确定这是否是一种好的做法，但它达到了目的。

我认为每个Javascript实现都将支持这一点，并且这样做不会有任何危险。通常用HTML/CSS代替简单的os风格的警告框。这样做意味着您不必更改现有的代码!这一事实使得Javascript非常棒。

When it comes to js browser functions window.alert is pre-eminent and most well known, people who don't know js know alert() -- rest assured it is supported in all browsers in use today and your code snippet is as well. However, I wouldn't override (well this is more like refactoring rather than override in the OOP sense) alert() for a particular use case as yours because when you actually need to use alert() with no template, and you probably will, then you'll need another non-alert function to do so.

超铃报警功能无危险。每个浏览器都支持它。

例如:

// function over riding. Redirecting to Console with Firebug installed.
function alert(message) { 
    console.info(message);
} 

alert('This is an override.');

我做的一个快速破解来找到警报来自哪里，是去控制台，然后输入这个

function alert(message) { 
  console.info(message);
  debugger;
} 

正如在许多其他答案中所述，您可以使用

window.alert = null

or

window.alert = function(){}

然而，这并不一定会覆盖Window构造函数原型上的函数(注意大写的W)，所以黑客仍然可以输入:

Window.prototype.alert.apply(window, ["You were hacked!"]);

因此，你还需要重写该函数:

Window.prototype.alert = null

or

Window.prototype.alert = function(){}