php和html怎么結(jié)合，我要做seesion驗(yàn)證啊。。。

只能用模版技術(shù)嗎，我這個(gè)界面是個(gè)靜態(tài)界面，代碼量很大，，，不想大概 我應(yīng)該怎么去做？？？能不能給個(gè)demo

這樣寫肯定是不ok的。。。。求各位大佬指教

后臺(tái)登錄處理代碼

<?php
header("Content-type:text/html;Charset=utf8");
session_start();
//登錄處理界面 logincheck.php
//判斷是否按下提交按鈕
if(isset($_POST["hidden"]) && $_POST["hidden"] == "hidden")
{
    //將用戶名和密碼存入變量中，供后續(xù)使用
    $user = trim($_POST["username"]);//trim()函數(shù)移除字符串兩側(cè)的空白字符
    $psw = md5(trim($_POST["userpwd"]));//密碼使用md5()加密一次，存入數(shù)據(jù)庫(kù)
    $code = $_POST["code"];
    if($user == "" || $psw == "")
    {
        //用戶名或者密碼其中之一為空，則彈出對(duì)話框，確定后返回當(dāng)前頁(yè)的上一頁(yè)
        echo "<script>alert('請(qǐng)輸入用戶名或者密碼！'); history.go(-1);</script>";
    }else if($code != $_SESSION[' ver_code']){
        echo "<script>alert('驗(yàn)證碼不正確，請(qǐng)重新輸入！'); history.go(-1);</script>";
    }
    else
    { //確認(rèn)用戶名密碼驗(yàn)證碼不為空，則連接數(shù)據(jù)庫(kù)
        $conn = mysqli_connect("localhost","userdb","wRXxAG8eMb");//數(shù)據(jù)庫(kù)帳號(hào)密碼為安裝數(shù)據(jù)庫(kù)時(shí)設(shè)置
        if(mysqli_errno($conn)){
            echo mysqli_errno($conn);
            exit;
        }
        mysqli_select_db($conn,"userdb");
        mysqli_set_charset($conn,'utf8');
        $sql = "select username,userpwd from user where username = '$user' and userpwd = '$psw'";
        $result = mysqli_query($conn,$sql);
        $num = mysqli_num_rows($result);
        if($num)
        {
            //seesion登錄認(rèn)證
            
            $_SESSION["username"]="username";
            
            
            echo "<script>alert('成功登錄'); window.location.href='../index.html';</script>";
        }
        else
        {
            echo "<script>alert('用戶名或密碼不正確！');history.go(-1);</script>";
        }
    }
}
else
{
    echo "<script>alert('提交未成功！');</script>";
}

?>