window.onload =function(){

//1、獲取元素 catch element

var container=document.getElementById('container');

var list=document.getElementById('list');

var buttons=document.getElementById('buttons').getElementsByTagName('span');

var prev=document.getElementById('prev');

var next=document.getElementById('next');

next.onclick=function(){

list.style.left=parseInt(list.style.left)-600+'px';

console.log('yyyy');

}

prev.onclick=function(){

list.style.left=parseInt(list.style.left)+600+'px';

console.log('xxxx');

}

}