用javascript实现tab切换

    <div id="btn">
        <input type="button" value="tab1" class="active">
        <input type="button" value="tab2">
        <input type="button" value="tab3">
        <div style="display:block;">
            111111
        </div>
        <div>
            222222
        </div>
        <div>
            333333
        </div>        
    </div>

        .active{
            background:yellow;
        }

        #btn div {
            display: none;
            width:200px;
            height:200px;
            border: 1px solid #000;
        }

    <script>
        window.onload =function(){
            var btn=document.getElementById(‘btn‘);
            var tab=btn.getElementsByTagName(‘input‘);
            var box1=btn.getElementsByTagName(‘div‘);
            for(var i=0;i<tab.length;i++){
                tab[i].index=i;
                tab[i].onclick=function(){
                     for(var i=0;i<tab.length;i++){ //再次遍历是为了清空样式
                        tab[i].className=‘‘;
                        box1[i].style.display=‘none‘;

                    }
                    this.className= ‘active‘; //给当前点击按钮添加active类
                    box1[this.index].style.display=‘block‘;
                }
            }

        };

    </script>