?var nav = document.getElementById('part1').getElementsByTagName('li'); var sub = []; for (var i=0;i<nav.length;i++){ ?if(nav[i].className=="onclick"){ ? sub.push(nav[i]); ?}// ?if(i==nav.length-1)// ?{// ? break;// ?} } for(var i=0;i<sub.length;i++){ ?sub[i].onmouseover = function() { ? var lag = this.getElementsByTagName('ul');// ? console.log(lag); ? lag.style.setProperty('display','block');// ? lag.setAttribute("class","nav-dis");// ? lag.getAttribute("display");//lag.style.cssText="display:block";//lag.style.display ="display:none";//這些方法全跪了//通過console.log發(fā)現(xiàn)他的參數(shù)是這樣的//[ul.list-style.list-inline]//length:1//0:ul.list-style.list-inline//__proto__:HTMLCollection//然后用一種改變的方式提示lag和后面的方法未定義 ?} }