diff --git a/frontend/Web/admin.html b/frontend/Web/admin.html
index 22c599c..69fb7e7 100644
--- a/frontend/Web/admin.html
+++ b/frontend/Web/admin.html
@@ -70,7 +70,7 @@
   <div class="main-content">
     <nav>
       <a href="#">Search Books</a>
-      <a href="#">Purchase Books</a>
+      <a href="/buy">Purchase Books</a>
     </nav>
     <div class="content">
       This is content.
diff --git a/frontend/Web/buy.html b/frontend/Web/buy.html
new file mode 100644
index 0000000..bf254d7
--- /dev/null
+++ b/frontend/Web/buy.html
@@ -0,0 +1,124 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <title>Buy - ZYM's Book Store</title>
+  <link rel="stylesheet" href="basic.css">
+  <style>
+    .buy-box {
+            width: 300px;
+            padding: 20px;
+            border: 1px solid #ccc;
+            background-color: #fff;
+            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
+            position: absolute;
+            top: 50%;
+            left: 50%;
+            transform: translate(-50%, -50%);
+        }
+
+        input {
+            width: 100%;
+            padding: 10px;
+            margin-bottom: 10px;
+            box-sizing: border-box;
+        }
+
+        button {
+            width: 100%;
+            padding: 10px;
+            background-color: #4caf50;
+            color: #fff;
+            border: none;
+            cursor: pointer;
+        }
+
+    .info-box {
+      width: 300px;
+      padding: 20px;
+      border: 1px solid #ccc;
+      background-color: #fff;
+      box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
+      position: absolute;
+      top: 50%;
+      left: 50%;
+      transform: translate(-50%, -50%);
+    }
+  </style>
+</head>
+<body>
+
+  <header>
+    <h1>ZYM's Book Store</h1>
+    <div class="user-bar">
+      <span>Welcome, <span id="username">[Guest]</span></span>
+      <div class="action-button-container" onmouseover="showDropdown()" onmouseout="hideDropdown()">
+        <div class="action-button">Actions</div>
+        <div class="dropdown">
+          <div class="dropdown-content">
+            <a href="/login">Login</a>
+            <a href="#" onclick="(async () => { await Request('logout'); await UpdateUserInfo(); location.reload();})(); return false;">Logout</a>
+            <a href="/register">Register</a>
+            <a href="/passwd">Change Password</a>
+            <a href="/admin">Admin Panel</a>
+          </div>
+        </div>
+      </div>
+    </div>
+  </header>
+
+  <div class="main-content">
+    <nav>
+      <a href="#">Search Books</a>
+      <a href="/buy">Purchase Books</a>
+    </nav>
+    <div class="content">
+      <div class="buy-box">
+        <form onsubmit="console.log('trying passwd'); TryBuy(); return false;">
+            <input id="isbn" type="text" placeholder="ISBN" required>
+            <input id="quantity" type="text" placeholder="Quantity" required>
+            <button type="submit">Buy</button>
+        </form>
+    </div>
+    </div>
+  </div>
+
+  <script src="/socket.io/socket.io.js"></script>
+  <script src="/communication.js"></script>
+  <script src="/basic.js"></script>
+  <script>
+    document.addEventListener('SessionReady', async () => {
+      await UpdateUserInfo();
+      if((await GetMyPrivilege())<1)
+      {
+        document.querySelector('.buy-box').style.display = 'none';
+        document.querySelector('.content').innerHTML = '<div class="info-box"><h2>Please log in first.</h2><p>Redirecting to home page in 3 seconds...</p></div>';
+        setTimeout(function(){window.location.href="/";},3000);
+      }
+    });
+    function isFloat(str) {
+      // 使用parseFloat尝试将字符串转换为浮点数
+      var floatValue = parseFloat(str);
+
+      // 使用isNaN检查是否成功转换，并确保不是Infinity或NaN
+      return !isNaN(floatValue) && isFinite(floatValue);
+    }
+    async function TryBuy()
+    {
+      console.log("TryBuy called");
+      var isbn = document.getElementById("isbn").value;
+      var quantity = document.getElementById("quantity").value;
+      var ret=await Request("buy "+isbn+" "+quantity);
+      if(isFloat(ret))
+      {
+        // 删除注册框，在中间显示“注册成功”，三秒后自动跳转到首页
+        document.querySelector('.buy-box').style.display = 'none';
+        document.querySelector('.content').innerHTML = '<div class="info-box"><h3>Successfully bought book with ISBN='+isbn+'</h3><h3>Used '+ret+'RMB</h3><p>Auto refreshing page in 10 seconds...</p></div>';
+        setTimeout(function(){location.reload();},10000);
+      }
+      else alert("Invalid bookname or quantity");
+    }
+  </script>
+  <script src="/sessioninit.js"></script>
+</body>
+</html>
\ No newline at end of file
diff --git a/frontend/Web/index.html b/frontend/Web/index.html
index f47efd5..b740e34 100644
--- a/frontend/Web/index.html
+++ b/frontend/Web/index.html
@@ -29,7 +29,7 @@
   <div class="main-content">
     <nav>
       <a href="#">Search Books</a>
-      <a href="#">Purchase Books</a>
+      <a href="/buy">Purchase Books</a>
     </nav>
     <div class="content">
       <!-- Your content goes here -->
diff --git a/frontend/Web/index.js b/frontend/Web/index.js
index a0c4fb8..ffc0375 100644
--- a/frontend/Web/index.js
+++ b/frontend/Web/index.js
@@ -195,6 +195,10 @@ app.get('/admin', (req, res) => {
   res.sendFile(join(__dirname, 'admin.html'));
 });
 
+app.get('/buy', (req, res) => {
+  res.sendFile(join(__dirname, 'buy.html'));
+});
+
 server.listen(3000, () => {
   console.log('server running at http://localhost:3000');
 });
\ No newline at end of file
diff --git a/frontend/Web/login.html b/frontend/Web/login.html
index b4831eb..5166ad7 100644
--- a/frontend/Web/login.html
+++ b/frontend/Web/login.html
@@ -69,7 +69,7 @@
   <div class="main-content">
     <nav>
       <a href="#">Search Books</a>
-      <a href="#">Purchase Books</a>
+      <a href="/buy">Purchase Books</a>
     </nav>
     <div class="content">
       <div class="login-box">
diff --git a/frontend/Web/passwd.html b/frontend/Web/passwd.html
index 3d8e897..8725490 100644
--- a/frontend/Web/passwd.html
+++ b/frontend/Web/passwd.html
@@ -70,7 +70,7 @@
   <div class="main-content">
     <nav>
       <a href="#">Search Books</a>
-      <a href="#">Purchase Books</a>
+      <a href="/buy">Purchase Books</a>
     </nav>
     <div class="content">
       <div class="passwd-box">
diff --git a/frontend/Web/register.html b/frontend/Web/register.html
index 8bd6bb9..c241121 100644
--- a/frontend/Web/register.html
+++ b/frontend/Web/register.html
@@ -70,7 +70,7 @@
   <div class="main-content">
     <nav>
       <a href="#">Search Books</a>
-      <a href="#">Purchase Books</a>
+      <a href="/buy">Purchase Books</a>
     </nav>
     <div class="content">
       <div class="register-box">
