javascript - 了解 window.event 属性及其用法

Question

我不明白 window.event 或 window.event.srcElement 背后的动机。在什么情况下应该使用它？它在 DOM 中究竟代表什么？

Answer 1

这是什么w3school says关于事件对象:

Events are actions that can be detected by JavaScript, and the event object gives information about the event that has occurred.

Sometimes we want to execute a JavaScript when an event occurs, such as when a user clicks a button.

您可以使用以下方式处理事件:

node.onclick = function(e) {
  // here you can handle event. e is an object.
  // It has some usefull properties like target. e.target refers to node
}

但是 Internet Explorer 不会将事件传递给处理程序。相反，您可以使用在事件触发后立即更新的 window.event 对象。所以处理事件的跨浏览器方式:

node.onclick = function(e) {
  e = e || window.event;
  // also there is no e.target property in IE.
  // instead IE uses window.event.srcElement
  var target = e.target || e.srcElement;
  // Now target refers to node. And you can, for example, modify node:
  target.style.backgroundColor = '#f00';
}