JavaScript 学习笔记— —Event（二）

// 实现一个通用的，跨多种浏览器的时间绑定函数
function addEvent(el, type, fn) {
  if (window.addEventListener) {
    el.addEventListener(type, fn, false);
  } else if (window.attachEvent) {
    el.attachEvent(‘on‘ + type, fn);
  } else {
    el[‘on‘ + type] = fn;
  }
}

var btn = document.getElementById("myButton");
btn.attachEvent("onclick", function(event) {
    alert(this === window);              // true
    alert(this.id)                       // undefined
});

var btn = document.getElementById("myButton");
btn.addEventListener("click", function(event) {
    alert(this === btn);                  // true
    alert(this.id);                       // myButton
    alert(this === event.currentTarget);  // true
});