<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form onsubmit="return false;">
<br>
<textarea id="responseText" style="width: 500px; height: 150px;rows=10;"></textarea>
<input type="button" value="开始" onclick="send_msg()">
</form>
</body>
</html>
如图按钮与下边对其，如何使得按钮与框图上边对齐
