在线实例：http://www.lgyweb.com/tab/
分析个人用原生JS获取类名元素的代码：
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getByClassName:function(className,parent){
var elem = [],
node = parent != undefined&&parent.nodeType==1?parent.getElementsByTagName('*'):document.getElementsByTagName('*'),
p = new RegExp("(^|\\s)"+className+"(\\s|$)");
for(var n=0,i=node.length;n<i;n++){
if(p.test(node[n].className)){
elem.push(node[n]);
}
}
return elem;
}
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parent参数是可选的，但需要先判断它是否存在，且是节点dom元素 parent != undefined&&parent.nodeType==1 ，nodeType == 1可以判断节点是否为dom元素，在火狐浏览器里面，空白也算是节点（.childnodes），用这个属性就判断是否为dom元素，排除空白符.
移除元素的类名：
var cur = new RegExp(this.sCur,'g'); //this.sCur就是类名，这里是用变量保存 如：this.sCur = "cur";
this.oTab_btn[n].className = this.oTab_btn[n].className.replace(cur,'');
以下为详细代码：
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function LGY_tab(option){
this.oTab_btn = this.getDom(option.tabBtn);//切换点击的元素
this.oTab_clist = this.getDom(option.tabCon); //切换的内容
this.sCur = option.cur; //激活的状态
this.type = option.type || 'click';
this.nLen = this.oTab_btn.length;
this.int();
}
LGY_tab.PRototype = {
getId:function(id){
return document.getElementById(id);
},
getByClassName:function(className,parent){
var elem = [],
node = parent != undefined&&parent.nodeType==1?parent.getElementsByTagName('*'):document.getElementsByTagName('*'),
p = new RegExp("(^|\\s)"+className+"(\\s|$)");
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);
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';
}
}
}
}
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