直接在input属性框中添加keyup事件
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script src="jquery.min.js"></script>
</head>
<body>
<div >
<tr>
<td>
输入：<input name="test" value="asdf" onkeyup="value=value.replace(/[^\d]/g,'')"></input>
</td>
</tr>
</div>
</body>
</html>