Question

我使用php制作了登录/注册系统。登录后我想向用户显示一个mesaage，欢迎$ username。但我面临一些问题。这是我的代码：

<?php 
    session_start();
    $username = $_SESSION['username'];
    $password = $_SESSION['password'];
    if(!$username && !$password)
    {
       header( 'Location: login.php' ) ;
    }
    else
   {
       echo '';
   }
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <title>Home | Incredible Saurav</title>
    <link rel="stylesheet" href="css/responsiveslides.css">
    <link href="css/bootstrap.min.css" rel="stylesheet">
    <link href="css/font-awesome.min.css" rel="stylesheet">
    <link href="css/main.css" rel="stylesheet">
    <link href="css/responsive.css" rel="stylesheet">
    <link rel="shortcut icon" href="images/ico/1.png">
    <script src="js/jquery.js"></script>
    <script src="js/bootstrap.min.js"></script>
    <script type="text/javascript" src="js/jquery-1.9.0.min.js"></script>
    <script>
  $(function() {
    $(".rslides").responsiveSlides();
  });
    </script>
    <script src="js/responsiveslides.min.js"></script>
    <script src="js/responsiveslides.js"></script>
</head>

<body>

    <header id="header" class="entry-header">

        <nav class="navbar1 navbar-inverse" role="banner" style="border-top: 5px solid #065157;">
            <div class="container">
                <div class="navbar-header">
                    <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
                        <span class="sr-only">Toggle navigation</span>
                        <span class="icon-bar"></span>
                        <span class="icon-bar"></span>
                        <span class="icon-bar"></span>
                    </button>
                    <a class="navbar-brand" href="index.html"><img src="images/logo.png" alt="logo"></a>
                </div>

                <div class="collapse navbar-collapse navbar-right">
                    <ul class="nav navbar-nav">
                        <li class="active"><a href="index.html">Home</a></li>
                        <li><a href="about.html">About Us</a></li>
                        <li><a href="faculties.html">Faculties</a></li>
                        <li><a href="picture.html">Picture Gallery</a></li>
                       <li><a href="contact.html">Contact</a></li>
                       <li><a href="login.php"><?php echo Welcome $username; ?></a></li>                        
                    </ul>
                </div>
            </div>
        </nav>      


                <div class="top-bar" style="border-bottom: 5px solid #065157;" >
            <div class="container" style="margin-top:90px;">
                <div class="row">
                    <div class="col-sm-6 col-xs-4">
                        <div class="top-number"><p><i class="fa fa-phone-square"></i>&nbsp; &nbsp;+91 9097678160</p></div>
                    </div>
                    <div class="">
                    <div class="col-sm-6 col-xs-8">
                       <div class="social">
                            <ul class="social-share">
                                <li class="saurav"><a href="http://facebook.com/incredible.100rav" title="Facebook"><i class="fa fa-facebook"></i></a></li>
                                <li class="saurav"><a href="http://twitter.com/incredible100rv" title="Twitter"><i class="fa fa-twitter"></i></a></li>
                                <li class="saurav"><a href="http://instagram.com/incredible.100rav" title="Instagarm"><i class="fa fa-instagram"></i></a></li> 
                                <li class="saurav"><a href="http://plus.google/saurav.chill05" title="Google-Plus"><i class="fa fa-google-plus"></i></a></li>
                                <li class="saurav"><a href="#"><i class="fa fa-skype" title="Skype"></i></a></li>
                            </ul>
                            <div class="search">
                                <form role="form">&nbsp; &nbsp;
                                    <i class="fa fa-search"></i>
                                    <input type="text" class="search-form" autocomplete="off" placeholder="Search">

                                </form>
                           </div>
                       </div>
                    </div>
</div>
                </div>
            </div>
        </div>

    </header>
    <div class="container">
                        <ul class="rslides">
                            <li><img src="images/1.jpg" alt=""></li>
                            <li><img src="images/2.jpg" alt=""></li>
                            <li><img src="images/3.jpg" alt=""></li>
                            <li><img src="images/4.jpg" alt=""></li>
                            <li><img src="images/5.jpg" alt=""></li>
                        </ul>
    </div>

    <section id="conatcat-info">
        <div class="container">
            <div class="row">
                <div class="col-sm-8">
                    <div class="media contact-info">
                        <div class="pull-left">
                            <i class="fa fa-phone"></i>
                        </div>
                        <div class="media-body">
                            <h2>Have a question question about our college?</h2>
                            <p>Call Us : +91-909-7678-160</p>
                        </div>
                    </div>
                </div>
            </div>
        </div>   
    </section>


    <footer id="footer" class="midnight-blue" style="border-bottom: 5px solid #065157;" >
        <div class="container">

               <div class="container">

     <center>
            <ul class="copyright">
               <li>&copy; Copyright Accurate College</li>
               <li>Designed by <a title="Incredible Saurav" href="http://www.facebook.com/incredible.100rav">Rahul Gautam</a></li>          
            </ul>

</div>






    </footer>


    </body>
</html>

请指出我的错误并予以纠正。谢谢!!

Answer 1

HTML中的以下更正：

<li><a href="login.php"><?php echo "Welcome, ".$_SESSION['username']; ?></a></li>

顺便说一下，你有条件的其他人完全没有目的，所以为了清晰，简洁和正确而删除它。

Answer 2

关于此代码：

<li><a href="login.php"><?php echo Welcome $username; ?></a></li>

目前，欢迎＆＃39; PHP将被理解为一个不存在的常量，但是在没有将它连接到变量之后，它只会抛出语法错误。我建议使用IDE（例如Netbeans），这样就可以看到这种错误而无需运行代码。

请改为：

<li>
    Welcome
    <a href="login.php"
        ><?php echo htmlspecialchars($username, ENT_HTML5) ?></a>
</li>

我已经将固定字符串作为HTML的一部分 - 没有任何价值将其添加到echo语句中。

我还将输出变量包装在函数中以编码任何尖括号，以过滤掉您网站上的任何XSS尝试。请记住，用户输入可能有害，需要谨慎对待。

我需要登录/注册系统的帮助

2 个答案: