index.html

<!-- Session 测试页面 -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <title>登录</title>
  </head>
  <body>
    <div>
      <label for="user">username:</label>
      <input type="text" name="user" id="user" />
    </div>
    <div>
      <label for="password">password:</label>
      <input type="text" name="password" id="password" />
    </div>
    <button type="button" id="login">login</button>
    <h1 id="data"></h1>

    <script>
      const login = document.getElementById("login");
      login.addEventListener("click", function(e) {
        const user = document.getElementById("user").value;
        const password = document.getElementById("password").value;
        if (!user || !password) {
          return;
        }
        const req = fetch("http://localhost:3000/login", {
          method: "post",
          body: `user=${user}&password=${password}`,
          headers: {
            "Content-Type": "application/x-www-form-urlencoded"
          }
        });
        req
          // .then(stream => {
          //   staream.text();
          // })
          .then(res => {
            document.getElementById("data").innerText = res;
          });
      });
    </script>
  </body>
</html>