JS中事件冒泡和事件捕获介绍

<div>
 <input type="button" value="测试事件冒泡" />
</div>

  var $input = document.getElementsByTagName("input")[0];
   var $div = document.getElementsByTagName("div")[0];
   var $body = document.getElementsByTagName("body")[0];
 
   $input.onclick = function(e){
      this.style.border = "5px solid red"
      var e = e || window.e;
      alert("red")
   }
   $div.onclick = function(e){
      this.style.border = "5px solid green"
      alert("green")
   }
   $body.onclick = function(e){
      this.style.border = "5px solid yellow"
      alert("yellow")
   }

$input.onclick = function(e){
  this.style.border = "5px solid red"
  var e = e || window.e;
  alert("red")
  e.sPropagation();
}

$input.addEventListener("click", function(){
  this.style.border = "5px solid red";
  alert("red")
}, true)
$div.addEventListener("click", function(){
  this.style.border = "5px solid green";
  alert("green")
}, true)
$body.addEventListener("click", function(){
  this.style.border = "5px solid yellow";
  alert("yellow")
}, true)