分析个人用原生JS获取类名元素的代码：
getByClassName:function(className,parent){ var elem = [], node = parent != undefined&&parent.nodeType==1?parent.getElementsByTagName('*'):document.getElementsByTagName('*'), p = new RegExp("(^|\s)"+className+"(\s|$)"); for(var n=0,i=node.length;n<i;n++){ if(p.test(node[n].className)){ elem.push(node[n]); } } return elem; }
parent参数是可选的，但需要先判断它是否存在，且是节点dom元素 parent != undefined&&parent.nodeType==1 ，nodeType == 1可以判断节点是否为dom元素，在火狐浏览器里面，空白也算是节点（.childnodes），用这个属性就判断是否为dom元素，排除空白符.
移除元素的类名：
var cur = new RegExp(this.sCur,'g'); //this.sCur就是类名，这里是用变量保存 如：this.sCur = "cur";
this.oTab_btn[n].className = this.oTab_btn[n].className.replace(cur,'');
调用例子：
<!doctype html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> <style type="text/css"> body,p,ul,li {padding: 0;margin: 0;} ul {list-style: none;} h3 {padding: 5px;background-color: #999;margin-bottom: 10px;} pre {border: 1px dotted #000;} .explan {padding: 10px;color: #333;line-height: 1.6;} .box {width: 300px;height:100px;border: 1px solid #ccc;} .box ul{height: 30px;line-height: 30px;} .box ul li {float: left;display: inline;width: 150px;text-align: center;background-color: #eee;cursor: pointer;} .box .tab-cur {background-color: #000;color: #fff;} .box p {display: none;padding: 30px;} /*tabB*/ #tabB {width: 450px;} .box .tab-cur02 {background-color: #025023;} </style> </head> <body> <div class="explan"> <strong>使用阅读 ：</strong> <br> {'tabBtn':'#tabA .tab-i','tabCon':'#tabA .tab-c','cur':'tab-cur'} 【必选】 <br> （1）'tabBtn':'#tabA .tab-i','tabCon':'#tabA .tab-c' 选择器：只支持 #id .className，(ID + 空格 + 类名) 【必选】<br> （2）'cur':'tab-cur'（默认） ：为切换按钮当前状态（类名）【必选】<br> （3）'type':'mouseover'|| 'clicl' 默认是点击 【可选】 </div> <h3>tabA</h3> <pre>new LGY_tab({'tabBtn':'#tabA .tab-i', 'tabCon':'#tabA .tab-c', 'cur':'tab-cur' }); </pre> <div class="box" id="tabA"> <ul> <li class="tab-i">btn-A</li> <li class="tab-i">btn-B</li> </ul> <p class="tab-c">con-A</p> <p class="tab-c">con-B</p> </div> <h3>tabB</h3> <pre>new LGY_tab({'tabBtn':'#tabB .tab-i', 'tabCon':'#tabB .tab-k', 'cur':'tab-cur02', 'type':'mouseover' }); </pre> <div class="box" id="tabB"> <ul> <li class="tab-i">btn-A</li> <li class="tab-i">btn-B</li> <li class="tab-i">btn-C</li> </ul> <p class="tab-k">con-A</p> <p class="tab-k">con-B</p> <p class="tab-k">con-C</p> </div> <script type="text/javascript" src="下方的代码段.js"></script> <script type="text/javascript"> // new LGY_tab({'tabBtn':'#tabA .tab-i', 'tabCon':'#tabA .tab-c', 'cur':'tab-cur' }); // new LGY_tab({'tabBtn':'#tabB .tab-i', 'tabCon':'#tabB .tab-k', 'cur':'tab-cur02', 'type':'mouseover' }); //test // new LGY_tab({'tabBtn':'#tabB .tab-j', 'tabCon':'#tabB .tab-k', 'cur':'tab-cur02', 'type':'mouseover' }); </script> </body> </html>
JS详细代码：
function LGY_tab(option){ this.oTab_btn = this.getDom(option.tabBtn);//切换点击的元素 this.oTab_clist = this.getDom(option.tabCon); //切换的内容 if(!this.oTab_btn || !this.oTab_clist) return; this.sCur = option.cur; //激活的状态 this.type = option.type || 'click'; this.nLen = this.oTab_btn.length; this.int(); } LGY_tab.prototype = { getId:function(id){ return document.getElementById(id); }, getByClassName:function(className,parent){ var elem = [], node = parent != undefined&&parent.nodeType==1?parent.getElementsByTagName('*'):document.getElementsByTagName('*'), p = new RegExp("(^|\s)"+className+"(\s|$)"); for(var n=0,i=node.length;n<i;n++){ if(p.test(node[n].className)){ elem.push(node[n]); } } return elem; }, getDom:function(s){ var nodeName = s.split(' '), p = this.getId(nodeName[0].slice(1)), c = this.getByClassName(nodeName[1].slice(1),p); if(!p || c.length==0) return null; return c; }, change:function(){ var cur = new RegExp(this.sCur,'g'); for(var n=0;n<this.nLen;n++){ this.oTab_clist[n].style.display = 'none'; this.oTab_btn[n].className = this.oTab_btn[n].className.replace(cur,''); } }, int:function(){ var that = this; this.oTab_btn[0].className += ' '+this.sCur; this.oTab_clist[0].style.display = 'block'; for(var n=0;n<this.nLen;n++){ this.oTab_btn[n].index = n; this.oTab_btn[n]['on'+this.type] = function(){ that.change(); that.oTab_btn[this.index].className +=' ' + that.sCur; that.oTab_clist[this.index].style.display = 'block'; } } } }