history对象

history.back() 返回上一页面

 //02.html
<p>02</p>
    <a href="html/03.html">03.html</a>

//03.html
<p>03</p>
    <button id="btn">btn</button>
    <script>
        var btn =  document.getElementById("btn");
        btn.onclick = function(){
            history.back();
        }
    </script>