求助下面是源代碼，求各位大佬幫忙解決 css *{margin:0;padding:0;font-family:微軟雅黑;} a,img{border:none;text-decoration:none;} ul,li{list-style-type:none;} #nav{width:1180px;overflow:hidden;margin:50px?auto?0?auto;padding:0?10px;background-color:#f3f3f3;} .tab_li{float:left;line-height:50px;width:125px;} .tab_li?a{display:block;text-align:center;font-size:16px;color:#333;} .tab_li:hover{background-color:#ddd;} #xinwen{width:1180px;overflow:hidden;margin:0?auto;height:450px;padding:0?10px;background-color:#fcfcfc;position:relative;} .tab_div{display:none;width:1180px;background-color:#fcfcfc;height:450px;line-height:450px;text-align:center;font-size:72px;color:#ccc;position:absolute;top:0;left:0;} js window.onload=function(){ var?oBdTab?=?document.getElementsByClassName("tab_div")[1]; var?oTab?=?document.getElementsByClassName("tab_div"); var?oLi?=?document.getElementsByClassName("tab_li")[1]; var?ali?=?document.getElementsByClassName("tab_li"); oBdTab.style.display?=?'block'; oLi.style.backgroundColor?=?'#ddd'; oLi.style.fontWeight?=?'bold'; for(var?i?=?0;i?<?ali.length;?i++){ ali[i].index?=?i; ali[i].onclick?=?function(){ for(var?i?=?0;i?<?oTab.length;?i++){ ali[i].style.backgroundColor?=?''; ali[i].style.fontWeight?=?''; oTab.style.display?=?''; } ali[this.index].style.backgroundColor?=?'#ddd'; ali[this.index].style.fontWeight?=?'bold'; oTab[this.index].style.display?=?'block'; } } } html <div?id="nav"> <ul> <li?class="tab_li"><a?href="###">熱點(diǎn)</a></li> <li?class="tab_li"><a?href="###">今日推薦</a></li> <li?class="tab_li"><a?href="###">直播</a></li> <li?class="tab_li"><a?href="###">視頻</a></li> <li?class="tab_li"><a?href="###">閱讀</a></li> </ul> </div> <div?id="xinwen"> <div?class="tab_div">熱點(diǎn)</div> <div?class="tab_div">今日推薦</div> <div?class="tab_div">直播</div> <div?class="tab_div">視頻</div> <div?class="tab_div">閱讀</div> </div>