alert（）在Chrome中不起作用 [英] alert() not working in Chrome

问题描述

'nuff说。我完全不知道为什么使用alert（）不行。它在Firefox中完美工作，但在Chrome中出现此错误。

解决方案

  window.alert = null; 
 alert（'test'）; //失败
 delete window.alert; // true 
 alert（'test'）; // win 
  

窗口是> DOMWindow ，并通过设置 window.alert ，正确的实现被屏蔽，即当访问 alert 它首先在窗口对象上查找它。通常情况下，这是找不到的，然后它通过原型链找到原生实现。但是，当手动将警报属性添加到窗口时，它会立即发现并且不需要上升原型链。使用 delete window.alert ，您可以删除窗口自己的属性，并再次公开 alert 的原型实现。这可能有助于解释：

  window.hasOwnProperty（'alert'）; // false 
 window.alert = null; 
 window.hasOwnProperty（'alert'）; // true 
 delete window.alert; 
 window.hasOwnProperty（'alert'）; // false 
  

'nuff said. I have absolutely no clue why using alert() there wouldn't work. It works perfectly in Firefox, but gives that error in Chrome.

解决方案

window.alert = null;
alert('test'); // fail
delete window.alert; // true
alert('test'); // win

window is an instance of DOMWindow, and by setting something to window.alert, the correct implementation is being "shadowed", i.e. when accessing alert it is first looking for it on the window object. Usually this is not found, and it then goes up the prototype chain to find the native implementation. However, when manually adding the alert property to window it finds it straight away and does not need to go up the prototype chain. Using delete window.alert you can remove the window own property and again expose the prototype implementation of alert. This may help explain:

window.hasOwnProperty('alert'); // false
window.alert = null;
window.hasOwnProperty('alert'); // true
delete window.alert;
window.hasOwnProperty('alert'); // false

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