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菜单栏展开和收起效果(纯js)

2024-07-09 13:52:59   220人阅读

2014年6月25日 15:36:29

需要关注的是: 

1.用cookie保存用户当前点击的菜单项,不打扰后端代码

2.通过数学计算得到要显示和隐藏的div

3.点击事件是动态绑定到a标签上的,因此当dom加载完后,再执行js,也就是写在onload里

HTML如下:

 1 <h3 class="titleH3" id="101">aaaa</h3> 2 <div class="subNav" id="1"> 3     <a href="#">1</a> 4     <a href="#">2</a> 5     <a href="#">3</a> 6 </div> 7 <h3 class="titleH3" id="102">bbbb</h3> 8 <div class="subNav" id="2"> 9     <a href="#">11</a>10     <a href="#">22</a>11     <a href="#">33</a>12 </div>

js如下:

 1 function showhide() 2 { 3     //绑定a链接的点击事件 4     //点击a链接的时候将id写进cookie 5     var arrSubNav = document.getElementsByClassName(‘subNav‘); 6     for (var i = 0; i < arrSubNav.length; i++) { 7         var arrHref = http://www.mamicode.com/arrSubNav[i].getElementsByTagName(‘a‘); 8         for (var j = 0; j < arrHref.length; j++) { 9             arrHref[j].onclick = function () {10                 var nodeParent = this.parentNode; //获取a链接所在的那个div块儿的id,注意,此处用this11                 var idParent = nodeParent.getAttribute(‘id‘);12                 document.cookie="userCheck="+idParent+";domain=***.***.com;path=/***"; //用cookie记录下用户当前的选择13             }14         }15     }16 17     //从cookie里取值,展开指定div18     userCheck = getUserCheckInfo();19     if (userCheck > 0) {20         for (var i = 0; i < arrSubNav.length; i++ ) {21             arrSubNav[i].style.display = ‘none‘;22         }23         document.getElementById(userCheck).style.display = ‘block‘;24     } else {25         document.getElementById(‘3‘).style.display = ‘block‘;26     }27 28     //点击标题时展开其下的菜单29     var arrTitle = document.getElementsByClassName(‘titleH3‘);30     for (var i = 0; i < arrTitle.length; i++) {31         arrTitle[i].onclick = function () {32             var idTitle = this.getAttribute(‘id‘);33             var idSubNav = idTitle % 100; //根据title的id获取子菜单div的id34             35             for (var i = 0; i < arrSubNav.length; i++ ) {36                 arrSubNav[i].style.display = ‘none‘;37             }38             document.getElementById(idSubNav).style.display = ‘block‘;39 40         }41     };42 }43 44 function getUserCheckInfo()45 {46     var strCookie = document.cookie;47     //将多cookie切割为多个名/值对 48     var arrCookie=strCookie.split("; "); 49     var userCheck = ‘0‘; 50     //遍历cookie数组，处理每个cookie对 51     for(var i=0;i<arrCookie.length;i++) { 52         var arr=arrCookie[i].split("="); 53         if("userCheck"==arr[0]){ 54             userCheck=arr[1]; 55             break; 56         } 57     } 58     return userCheck;59 }

 变量名没有起好,userCheck应该为userChoice或者userSelected更恰当,他是用来保存用户点击的菜单的id的


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