Code analysis of event bubbling ratio-JS Tutorial-php.cn

Code analysis of event bubbling ratio

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Release： 2018-07-14 16:06:57

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This article mainly introduces the code analysis of event bubbling ratio bubble. It has certain reference value. Now I share it with you. Friends in need can refer to it.

The concept of bubble is when When a child element triggers an event, the corresponding ancestor element will also trigger the same event

(provided that the parent element has also added the same event)

eg: The son has an onclick ancestor ten The eighth generation also has onclick

When clicking on the son, the click event of the eighteenth generation of the ancestor will also be triggered

Sometimes this situation will cause many problems, so we must prevent bubbling

Only clicked elements trigger events

Not all events will bubble

onblur onfocus onload onerror No

In fact, there are three processes for triggering events: Capture phase--->In target phase---->Bubbling phase

Standard browser bubble order child elements-->Parents-->body-->document-- ->window

IE child element-->parent-->body-->document

Next, it is very easy to write the code. Just do a compatibility process

<!doctype html>
<html>
 <head>
  <meta charset="UTF-8">
  <meta name="Generator" content="EditPlus®">
  <meta name="Author" content="">
  <meta name="Keywords" content="">
  <meta name="Description" content="">
  <title>阻止冒泡</title>
 </head>
 <body>
     <input type="button"  id="cancelBubble" value="取消冒泡"/>
    <script type="text/javascript">
          var btn=document.getElementById("cancelBubble");
          document.onclick=function(){
            alert("冒泡");
          }
          btn.onclick=function(event){
          var event=event||window.event;//兼容
          if(event && event.stopPropagation){
               
               event.stopPropagation();
          
          }
          else{
              //IE 678
             event.cancelBubble=true;
          }
           alert("没有冒泡");
          
          }
    </script>
 </body>
</html>

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