<img src="/upload2/attachments/cover/cover_css.png" width="95" height="84" id="img"> <div> <input type="text" value="0" id="num"> <button id="change">更改top值</button> <h1>This is a heading</h1> </div> <script> var img = document.getElementById('img'); var num = document.getElementById('num'); var btn = document.getElementById('change'); btn.onclick = function () { img.style.top = num.value + 'px'; } </script>