<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
</head>
<body>
<button id="up">上一张</button>
<button id="below">下一张</button>
<img id="img" src="../img/cat_five.jpg" />
<script>
var ups =document.getElementById('up');
var belows=document.getElementById('below');
var srcs = document.getElementById('img');
ups.onclick = function(){
img.src='../img/man-1.jpg';
}
belows.onclick =function(){
img.src='../img/cat_five.jpg'
}
</script>
</body>
</html>