?這是html的代碼<div id="container">??? ?<div class="box">??????? ?<div class="img_box"><img src="img/meinv5.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv2.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv3.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv7.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv3.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv6.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv2.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv7.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv2.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv5.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv2.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv3.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv7.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv5.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv6.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv2.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv7.jpg" /></div>???????? </div>???????? <div class="box">??????? ?<div class="img_box"><img src="img/meinv2.jpg" /></div>???????? </div>??? </div>這是js的代碼window.onload=function(){?imgNum("container","box");??}function imgNum(a,b){?var anum=document.getElementById(a)?var content=getbc(anum,b);?console.log(content.length);??}function getbc(a,b){?var barr=[];?var allcontent=a.getElementsByTagName("*");?for(var i=0;i<allcontent.length;i++){??if(allcontent[i].className==b){???barr.push(allcontent[i]);??}??return barr;?}}實際結果