```
代码如下
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>测试</title>
<style>
#mysteve {200px; height:30px; border:1px solid red;} #add {200px; height:30px; border:1px solid blue; display:none;}
</style>
</head>
<body>
<div id="mysteve">mysteve</div><div id="add">add</div>
</body>
</html>
<script>
window.onload = function () {
var ms = document.getElementById("mysteve");
var add = document.getElementById("add");
ms.onmouseover = function () {
add.style.display = "block";
};
ms.onmouseout = function () {
add.style.display = "none";
};
};
</script>
```