<html>
<head>
  <title>eventUtil</title>
  <script eventType="text/javascript">
    var eventUtil = {
      //監(jiān)聽(tīng)事件
      addListener: function(obj, eventType, fn) {
        if (obj.addEventListener) {
          obj.addEventListener(eventType, fn, false);
        } else if (obj.attachEvent) {
          obj.attachEvent('on' + eventType, fn);
        } else {
          obj['on' + eventType] = fn;
        }
      },
      //返回event對(duì)象
      getEvent: function(event) {
        return event || window.event;
        //return event ? event : window.event;
      },
      //返回目標(biāo)事件對(duì)象
      getTarget: function(event) {
        return event.target || event.srcobj;
      }，
      preventDefault: function(event) {
        if (event.preventDefault) {
          event.preventDefault();
        } else {
          event.returnValue = false;
        }
      },     
      removeListener: function(obj, eventType, fn) {
        if (obj.removeEventListener) {
          obj.removeEventListener(eventType, fn, false);
        } else if (obj.deattachEvent) {
          obj.detachEvent(eventType, fn);
        } else {
          obj['on' + eventType] = null;
        }
      },
      
      stopPropagation: function(event) {
        if (event.stopPropagation) {
          event.stopPropagation();
        } else {
          event.cancelBubble = true;
        }
      }
    };
  </script>
</head>
<body>
  <input eventType="button" value="click me" id="btn" />
  <p>event</p>
  <a>Hello word!</a>
  <script eventType="text/javascript">
  function addBtnListen(event)
  {
    var event = eventUtil.getEvent(event);
    var target = eventUtil.getTarget(event);
    alert("my name is kock");
    alert(event.eventType);
    alert(target);
    eventUtil.stopPropagation(event);

  }
  function getBodyListen(event)
  {
      alert("click body");
  }
  function getLinkListen(event)
  {
       alert("prevent default event");
       var event = eventUtil.getEvent(event);
       eventUtil.preventDefault(event);
  }
  window.onload=function()
  {
      var btn = document.getobjById("btn");
      var link = document.getobjsByTagName("a")[0];
      eventUtil.addListener(btn, "click", addBtnListen);
      eventUtil.addListener(document.body, "click", getBodyListen);
      eventUtil.addListener(link, "click",getLinkListen);
  }   
</script>
</body>
</html>

上面的方法能夠解決事件跨平臺(tái)問(wèn)題，接下來(lái)，我們看下charCode的屬性。

首先給eventUtil定義一個(gè)新方法，formatEvent,接受一個(gè)參數(shù)，即Event對(duì)象。

eventUtil.formatEvent=function(event)
{
  if(isIE&&isWin)
  {
   event.charCode=(event.type=="keypress")?event.keycode:0;
   event.eventphase=2;--表示冒泡階段，IE僅支持冒泡階段
  }
  return event;
}

二：關(guān)于冒泡中的target和currentTarget

target在事件流的目標(biāo)階段；currentTarget在事件流的捕獲，目標(biāo)及冒泡階段。只有當(dāng)事件流處在目標(biāo)階段的時(shí)候，兩個(gè)的指向才是一樣的，而當(dāng)處于捕獲和冒泡階段的時(shí)候，target指向被單擊的對(duì)象而currentTarget指向當(dāng)前事件的父級(jí)。

<div id="outer" style="background:#099"> 
      <p>我是目標(biāo)div</p>  ----點(diǎn)擊這部分，輸出：e.target.tagName : P || e.currentTarget.tagName : DIV      <p id="inner" style="background:#9C0">我是目標(biāo)p</p> ----點(diǎn)擊這部分，輸出：e.target.tagName : P || e.currentTarget.tagName : DIV

      <br> ----點(diǎn)擊這部分，輸出：e.target.tagName : DIV || e.currentTarget.tagName : DIV

</div>

//看下第二個(gè)變列：
<div id="outer" style="background:#099"> 
      <div>我是目標(biāo)div</div>  ----點(diǎn)擊這部分，輸出：e.target.tagName : DIV || e.currentTarget.tagName : DIV      <p id="inner" style="background:#9C0">我是目標(biāo)p</p> ----點(diǎn)擊這部分，輸出：e.target.tagName : P || e.currentTarget.tagName : DIV

      <br> ----點(diǎn)擊這部分，輸出：e.target.tagName : DIV || e.currentTarget.tagName : DIV

</div>

function getObj(id)
{ 
  return document.getElementById(id);   
} 
function addEvent(obj, event, fn)
{ 
  if(window.attachEvent)
  { 
   obj.attachEvent("on" + event, fn); 
  }
  else if(window.addEventListener)
  {  
   obj.addEventListener(event, fn, false); 
  } 
} 
function test(e)
{ 
  alert("e.target.tagName : " + e.target.tagName + "\n e.currentTarget.tagName : " + e.currentTarget.tagName); 
 } 
   var outer = getObj("outer"); 
   var inner = getObj("inner"); 
   //addEvent(inner, "click", test); 
   addEvent(outer, "click", test);

三：IE和DOM區(qū)別

	DOM	IE
獲取目標(biāo)	event.target	event.srcElement
獲取字符代碼	event.charCode	event.keyCode
阻止默認(rèn)行為	event.prevetDefault()	event.returnvalue=false
冒泡	event.stopPropagation()	event.cancelBubble=true

關(guān)于阻止默認(rèn)行為，比如，當(dāng)用戶右擊鼠標(biāo)時(shí)，如果你不想菜單彈出，則可以使用阻止默認(rèn)行為：

document.body.oncontextmenu=function(event)
{
  if(isIE)
  {
     var oEvent=window.event;
     oEvent.returnValue=false; //也可以直接是return false；阻止默認(rèn)行為
  }
  else
  {
    oEvent.preventDefault();
  }
}

四：鼠標(biāo)事件

<p>use your mouse to click and double click the red square</p>
<div style="width:100px;height:100px;background:red"
    onmouseover="handleEvent(event)"
    onmouseout="handleEvent(event)"
    onmousedown="handleEvent(event)" 
    onmouseup="handleEvent(event)"  
    onclick="handleEvent(event)" 
    ondblclick="handleEvent(event)" id="div1"
   >       
</div>
<p><textarea id="txt1" rows="5" cols="45"></textarea></p>
<!--檢測(cè)鍵盤(pán)事件-->
<p><input type="text" id="textbox" 
      onkeydown="handle(event)"
      onkeypress="handle(event)"
      onkeyup="handle(event)"
     ></p>
<p><textarea id="txt2" rows="10" cols="45"></textarea></p>

js文件如下：

function handleEvent(event)
{
  var oText=document.getElementById('txt1');
  oText.value+= "\n"+event.type;
  oText.value+= "\n target is "+(event.srcElement||event.target).id;
  oText.value+="\n at ("+event.clientX+","+event.clientY+")in the client";
  oText.value+="\n at ("+event.screenX+","+event.screenY+")in the client";
  oText.value+="\n button down is"+event.button;
  var arrKeys=[];
  oText.value+="\n relatedTarget is"+event.relatedTarget.tagName;
  //event.relatedTarget.tagName可以判斷鼠標(biāo)的來(lái)源和出處
}
function handle(event)
{
  var oText2=document.getElementById('txt2');
  oText2.value+="\n"+event.type;
  var arrKeys=[];
 if(event.shiftKey){arrKeys.push("Shift");}
 if(event.ctrlKey){arrKeys.push("Ctrl");}
 if(event.altKey){arrKeys.push("Alt");}
  oText2.value+="\n keydown is "+arrKeys;
}

以上這篇js中最容易被忽視的事件問(wèn)題大總結(jié)就是小編分享給大家的全部?jī)?nèi)容了，希望能給大家一個(gè)參考，也希望大家多多支持腳本之家。

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