<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
}
#outer {
width: 400px;
margin: 50px auto;
padding: 10px;
background-color: skyblue;
text-align: center;
}
img {
width: 100%;
}
</style>
<script>
window.onload = function() {
var prev = document.getElementById("prev");
var next = document.getElementById("next");
var img = document.getElementsByClassName("img")[0]; //获取img标签
prev.onclick = function() {
img.src = "img/1.jpg";
};
next.onclick = function() {
img.src = "img/2.jpg";
};
};
</script>
</head>
<body>
<div id="outer">
<img src="img/1.jpg" alt="机械">
<button id="prev">上一张</button>
<button id="next">下一张</button>
</div>
</body>
</html>
