Debugging notes for tab switching special effects based on javascript

Debugging notes for tab switching special effects based on javascript_javascript skills

WBOY

Release： 2016-05-16 15:07:29

Original

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The example in this article analyzes the debugging notes of javascript to implement tab switching for your reference. The specific content is as follows

Create a navigation bar. When the navigation bar element is clicked, the content below will change accordingly, and the element will display a special style.

js source code:

//导航栏单击变换内容
function tabSwitch(_this,num) {
 var tag = document.getElementById("nav9");
 var number = tag.getElementsByTagName("a"); //获取导航栏元素个数(getElementsByTagName是返回元素素组)
 var divNum = document.getElementsByClassName("eachDiv"); //获取导航元素对应的div个数
 for(var i=0;i<number.length;i++){ //number是一个数组，这里应该用number.length显示它的长度5
  number[i].className = " "; //清除所有导航栏元素的特殊样式
  divNum[i].style.display = "none"; //其他所有div都隐藏
 }
 _this.className = "l_nav1_no1"; //给当前导航栏元素添加样式
 var content = document.getElementById("l_no2_"+num); //当前导航栏元素对应的div
 content.style.display = "block"; //显示当前导航栏元素对应的div部分
}

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HTML code:

<!DOCTYPE html>
<html>
<head lang="en">
 <meta charset="UTF-8">
 <title></title>
 <script type="text/javascript" src="../MyJS/hao123.js"></script>
 <style type="text/css">
  .l_nav1 {
   height: 30px;
   padding-top: 8px;
  }
  .l_nav1 a{
   color: #3C3C3C;
   text-decoration: none;
   padding: 8px;
  }
  .l_nav1 a:hover,#l_nav1 a:active {
   color: green;
   text-decoration: underline;
  }
  .l_nav1 .l_nav1_no1 { /*“头条”*/
   color: green;
   text-decoration: none;
   border-top: solid 1px green;
  }

  .l_no2 {
   background-color: #ffffff;
   border: solid 1px #E0E0E0;
   height: 282px;
   width: 276px;
   overflow: scroll; /*当元素内容太大而超出规定区域时，内容会被修剪，但是浏览器会显示滚动条以便查看其余的内容。。*/
  }
  .l_no2 ul{  /*列表部分*/
   padding-left: 0px;
   line-height: 25px;
   font-size: 14px;;
  }
  .l_no2 ul li{
   list-style: none;
  }
  .l_no2 ul a{
   color: #3C3C3C;
   text-decoration: none;
  }
  .l_no2 ul a:active,.l_no2 ul a:hover {
   color: red;
   text-decoration: underline;
  }
 </style>
</head>
<body>
 <nav id="nav9" class="l_nav1">
  <a href="#" onclick="tabSwitch(this,1)" class="l_nav1_no1">头条</a>
  <a href="#" onclick="tabSwitch(this,2)">社会</a>
  <a href="#" onclick="tabSwitch(this,3)">娱乐</a>
  <a href="#" onclick="tabSwitch(this,4)">军事</a>
  <a href="#" onclick="tabSwitch(this,5)">体育</a>
 </nav>
 <div class="l_no2">
  <div id="l_no2_1" class="eachDiv" style="display: block"> <!--默认为该div显示-->
   <img src="../images/hao123/25.jpg" width="274px">
   <ul>
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  <div id="l_no2_5" class="eachDiv" style="display: none">
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  </div>
 </div>
</body>
</html>

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Rendering:

Debug notes:

1. Mistake 1:

var number = tag.getElementsByTagName("a").length;

(1) Error report:

(2) Explanation and correction:

**getElementsByTagName() returns the element group. If you take its length, number is just a number, so number[i].className = " "; will report an error. **

Correction:

var number = tag.getElementsByTagName("a");

2. Mistake 2:

 for(var i=0;i<number;i++){ 
  number[i].className = " "; //清除所有导航栏元素的特殊样式
  divNum[i].style.display = "none"; //其他所有div都隐藏
 }

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The number here should be a number, representing the number of elements in a. From error 1, we can know that to get the length of number, it should be changed to:

for(var i=0;i<number.length;i++){ //number是一个数组
  number[i].className = " "; //清除所有导航栏元素的特殊样式
   divNum[i].style.display = "none"; //其他所有div都隐藏
  }

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The above is the entire content of this article, I hope it will be helpful to everyone’s study.