Javascript Event（事件）的传播与冒泡

2019-11-19 17:48:29

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特性说明和原理图：

标准浏览器和Ie9+浏览器都支持事件的冒泡和捕获，而IE8-浏览器只支持冒泡
标准和Ie9+浏览器用stopPropagation()或cancelBubble阻止事件传播，而ie8-用e.cancelBubble属性来阻冒泡，注意ie9不支持cancelBubble属性（设置后不生效），但chrome、safari、opera、firefox都支持cancelBubble属性。
Ie8-用attachEvent为dom元素添加一个事件，但必须在事件名前加上on，此类事件只能在元素的冒泡阶段。
stopPropagatin()方法用于阻止事件的传播，如果设置在捕获阶段，则目标和冒泡阶段不会被执行；
cancelBubble属性只能阻止冒泡阶段，对捕获和目标阶段的事件不能阻止
preventDefault()和window.event.returnValue用于标准浏览器和ie9+，都可以阻止默认事件。ie8-可以用returnValue，preventDefault()。

示例代码(ie8-示例不提供)

html代码

<body class="body" >  <div class="log"></div> <input type="text" id="inTxt" name="intxt" /><div class="wrap"> <div class="cont">  <button type="button" class="button" id="btn">按钮</button>  <select name="stopType" id="stopType">    <option value="1">StopPropagation</option>    <option value="2">cancelBubble</option>  </select>  <button type="button" class="button" id="btnReject">cont阻止捕获或冒泡</button> </div></div></body>

层级关系：body->wrap->cont->button，可以对照上面的原理

Js代码

$(function(){    var $log = $('.log'),       $wrap = $('.wrap'),      $cont = $('.cont'),      $btn = document.getElementById('btn'),      $stopType = $('#stopType'),      $body = $('body'),      $inTxt = $('#inTxt'),      $btnReject = $('#btnReject');    var ePhase = ["","捕获","目标","冒泡"]    var setBorderColor = function( $dom, color, time,event){      $dom = $($dom);      $log.html($log.html() + $dom.attr('class') + '[' + ePhase[event.eventPhase] + ']' + '<br/>')      var timeIndex = window.setTimeout(function(){         $dom.css({        'borderColor': color,        'borderWidth': '4px'      });      }, time);    }      //捕获    $body[0].addEventListener('click',function(event){       $log.html($log.html() + "-------------------<br>");      setBorderColor($body,'#0866ff ',0,event);    },true);      $wrap[0].addEventListener('click',function(event){      setBorderColor($wrap,'yellow',2000,event);     },true);    $cont[0].addEventListener('click',function(event){      event = event || window.event;      if( $stopType.val() == '1' ){        event.stopPropagation();      }else{        event.cancelBubble = true;      }      setBorderColor($cont,'green',1000,event);      },true);     $btn.addEventListener('click', function(event){       setBorderColor($btn,'red',0,event);    },true);    $btnReject[0].addEventListener('click',function(event){       setBorderColor($btnReject,'gray ',0,event);    },true);    //冒泡    $body[0].addEventListener('click',function(event){      setBorderColor($body,'#0866ff ',0,event);    },false);     $wrap[0].addEventListener('click',function(event){      setBorderColor($wrap,'yellow',2000,event);     },false);     $cont[0].addEventListener('click',function(event){      setBorderColor($cont,'green',1000,event);      },false);     $btn.addEventListener('click', function(event){       setBorderColor($btn,'red',0,event);    },false);    $btnReject[0].addEventListener('click',function(event){       setBorderColor($btnReject,'gray ',0,event);    },false);    //阻止默认事件    $inTxt.keypress(function(event){      //event.preventDefault();       window.event.returnValue = false;      $body.append( String.fromCharCode( event.keyCode ));    });  });