html form
<html>
<head>
<title>
html index
</title>
</head>
<body>
<!-- form，点击提交后，访问demo.php.而我们一般用于form形成表单后，触发后端的api -->
<form action="demo.php" method="get">
Your Name: <input type="text",name="username"><br>
Your Passwd: <input type="text",name="passwd"><br>
<input type="submit" value="提交">
</form>
</body>
</html>
