表单内必须有 <input type=”submit” value=”submit”> 才能实现回车提交效果
<!DOCTYPE html>
<html>
<head>
<meta charset=”utf-8″>
<title></title>
</head>
<body>
<form method=”post”>
<label>UserName<input name=”username” type=’text’></label>
<br>
<label>PassWord<input name=”password” type=’password’></label>
<br>
<input type=”submit” value=”submit”>
</form>
</body>
</html>