php未定义索引错误mysql css if语句答案

【问题标题】：php undefined index error mysql css if statementphp未定义索引错误mysql css if语句
【发布时间】：2018-09-26 08:31:33
【问题描述】：

我正在使用 php html 和 MySQL 数据库编写 Web 应用程序。我正在尝试实现一个 if，如果数据库中的该行具有某个值，它将更改其显示方式的 CSS。所以在我的数据库中有项目，如果项目完成（com =“yes”）它应该显示为绿色。在 dbconnect.php 我有以下内容：

<?php
session_start();

$username = "";
$email = "";
$projtitle = "";
$deadline = "";
$del1 = "";
$del2 = "";
$del3 = "";
$errors = array();

 //Connect to the database
    $db = mysqli_connect('localhost', 'root', '', 'hons');

//If the add project button is clicked
if(isset($_POST['addproj'])) {
    $projtitle = mysqli_real_escape_string($db, $_POST['projtitle']);
    $del1 = mysqli_real_escape_string($db, $_POST['del1']);
    $del2 = mysqli_real_escape_string($db, $_POST['del2']);
    $del3 = mysqli_real_escape_string($db, $_POST['del3']);
    $deadline = mysqli_real_escape_string($db, $_POST['deadline']);
    $colour = mysqli_real_escape_string($db, $_POST['colour']);

    //Insert into the database
        $sql = "INSERT INTO projects (title, del1, del2, del3, deadline)
                    VALUES ('$projtitle', '$del1', '$del2', '$del3', '$deadline')";
        mysqli_query($db, $sql);
};

//If the project complete button is clicked
    if(isset($_POST['projcom'])) {
        $com = yes;

        //Insert into database
        $sql = "INSERT INTO evals (com)
VALUES ('$com')";
        mysqli_query($db, $sql);
};

//If the project not complete button is clicked
if(isset($_POST['notcom'])) {
    $com = no;

    //Insert into database
    $sql = "INSERT INTO evals (com)
VALUES ('$com')";
    mysqli_query($db, $sql);
};

这是我的实际网页代码：

<?php

session_start();

if(!isset($_SESSION['username'])){
    $_SESSION['msg'] = "You must log in first";
    header('location: index.php');
}
if(isset($_GET['logout'])){
    session_destroy();
    unset($_SESSION['username']);
    header("location: index.php");
}

?>

<?php include ('dbconnect.php') ?>

<!DOCTYPE html>
<html lang="en">
<head>

    <title>UPM</title>

    <meta charset="UTF-8">

    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>

    <style>

        .col-sm-4{
            display: inline-block;
            padding: 50px 50px;
            border-style: solid;
            border-width: 3px;
            border-radius: 5px;
            font-size: 16px;
        }

        .col-sm-4.completed{
            display: inline-block;
            padding: 50px 50px;
            border-style: solid;
            border-width: 3px;
            border-radius: 5px;
            font-size: 16px;
            border-color: green;
            font-color: green;
        }

        .col-sm-4.notcompleted{
            display: inline-block;
            padding: 50px 50px;
            border-style: solid;
            border-width: 3px;
            border-radius: 5px;
            font-size: 16px;
            font-color: red;
            border-color: red;
        }

        .jumbotron {
            background-color: #f4511e;
            color: #ffffff;
            padding: 100px 25px;

        }

        .bg-grey{
            background-color: #f6f6f6;
        }

        .container-fluid{
            padding: 60px 50px;
        }

        .logo {
            font-size: 200px;
        }

        @media screen and (max-width: 768px) {

            .col-sm-4 {
                text-align: center;
                margin: 25px 0;
            }

        }

        .navbar {
            margin-bottom: 0;
            background-color: #f4511e;
            z-index: 9999;
            border: 0;
            font-size: 12px !important;
            line-height: 1.42857143 !important;
            letter-spacing: 4px;
            border-radius: 0;
        }

        .navbar li a, .navbar .navbar-brand {
            color: #fff !important;
        }

        .navbar-nav li a:hover, .navbar-nav li.active a {
            color: #f4511e !important;
            background-color: #fff !important;
        }

        .navbar-default .navbar-toggle {
            border-color: transparent;
            color: #fff !important;

        }

    </style>
</head>



<body id="MyProjects" data-spy="scroll" data-target=".navbar" data-offset="60">



<nav class="navbar navbar-default navbar-fixed-top">

    <div class="container">

        <div class="navbar-header">

            <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#myNavbar">

                <span class="icon-bar"></span>

                <span class="icon-bar"></span>

                <span class="icon-bar"></span>

            </button>

            <a class="navbar-brand">

                <!-- logo not working-->

                <!-- <IMG SRC="images/UPMLogo.jpg" width="230px" height="158px">-->

            </a>

        </div>

        <div class="collapse navbar-collapse" id="myNavbar">

            <ul class="nav navbar-nav navbar-right">

                <li><a href="home.php">HOME</a></li>

                <li><a href="myprojects.php">MY PROJECTS</a></li>

                <li><a href="eval.php">EVALUATIONS</a></li>

                <li><a href="#pricing">MY STATS</a></li>

                <li><a href="hints.php">HINTS & TIPS</a></li>

                <li><a href="home.php?logout='1'">LOG OUT</a></li>

            </ul>

        </div>

    </div>

</nav>



<div class="jumbotron text-center">

    <h1 id =SiteTitle> Welcome to your MyProjects page! </h1>

    <h3>Here you will be able to enter all of your university projects along with their deliverable's and deadlines. You can mark your projects as successful or unsuccessful depending on whether you met the deadline.
        It is a great way to visually track all of your projects!</h3>

</div>


<div class=""container-fluid">

<p>
To get add a project click on the plus symbol. If a project is completed on time with all the deliverables' mark it with the tick! Otherwise click on the X.
</p>
</div>

<div class="container-fluid text-center bg-grey">
    <div class="row text-center">
        <div>
                <form method="post" action="myprojects.php">

                    <div class=""input-group>
                    Project Title :<br>
                    <input type="text" name="projtitle"><br>
                    </div>
                    <div class=""input-group>
                    Deliverable 1 :<br>
                    </div>
                    <div class=""input-group>
                    <input type="text" name="del1"><br>
                    Deliverable 2 :<br>
                    </div>
                    <div class=""input-group>
                    <input type="text" name="del2"><br>
                    </div>
                    <div class=""input-group>
                    Deliverable 3 :<br>
                    <input type="text" name="del3"><br>
                    </div>
                    <div class=""input-group>
                    Final Deadline Date: <br>
                    <input type="date" name="deadline"><br>
                    </div>
                    <div class=""input-group>
                    Choose a Colour: <br>
                    <input type="color" name="colour"><br><br>
                    </div>
                <button type="submit" class="btn" name="addproj">+</button>
                <p><strong>Click me, click me!</strong></p>
                </form>
            </div>
        </form>
        </div>

    <!--Display projects-->
    <?php
    $sql = "SELECT * FROM projects";
    $result = mysqli_query($db, $sql);
    while ($row = mysqli_fetch_array($result)){
        //if com is equal to yes then else the normal echo
        if($row['com'] == yes){
            echo "<div id='projcompleted' class='col-sm-4.completed'>";
            echo "<p>" . $row['title'] . "</p>";
            echo "<p>Deliverables: </p>";
            echo "<p>" . $row['del1'] . "</p>";
            echo "<p>" . $row['del2'] . "</p>";
            echo "<p>" . $row['del3'] . "</p>";
            echo "<p>Deadline date:</p>";
            echo "<p>" . $row['deadline'] . "</p>";
            echo "<p>Deadline met and project complete!</p>";
            echo "<button type=\"submit\" class=\"btn\" name=\"projcom\">√</button> <button type=\"submit\" class=\"btn\" name=\"notcom\">X</button>";
            echo "</div>";
        }
        elseif ($row['com'] == no){
            echo "<div id='projnotcom' class='col-sm-4.notcompleted'>";
            echo "<p>" . $row['title'] . "</p>";
            echo "<p>Deliverables: </p>";
            echo "<p>" . $row['del1'] . "</p>";
            echo "<p>" . $row['del2'] . "</p>";
            echo "<p>" . $row['del3'] . "</p>";
            echo "<p>Deadline date:</p>";
            echo "<p>" . $row['deadline'] . "</p>";
            echo "<p>Deadline missed/project incomplete! :(</p>";
            echo "<button type=\"submit\" class=\"btn\" name=\"projcom\">√</button> <button type=\"submit\" class=\"btn\" name=\"notcom\">X</button>";
            echo "</div>";
        }
        else {
            echo "<div id='proj' class='col-sm-4'>";
            echo "<p>" . $row['title'] . "</p>";
            echo "<p>Deliverables: </p>";
            echo "<p>" . $row['del1'] . "</p>";
            echo "<p>" . $row['del2'] . "</p>";
            echo "<p>" . $row['del3'] . "</p>";
            echo "<p>Deadline date:</p>";
            echo "<p>" . $row['deadline'] . "</p>";
            $target = strtotime($row['deadline']);
            $today = time();
            $difference = $target - $today;
            $days = (int)($difference / 86400);
            print $days;
            echo "<p>days until deadline</p>";
            echo "<button type=\"submit\" class=\"btn\" name=\"projcom\">√</button> <button type=\"submit\" class=\"btn\" name=\"notcom\">X</button>";
            echo "</div>";
        }
    }

    ?>


</body>

</html>

错误不断将我指向我有项目的 if 语句完成是或否的行（com = yes 和 com = no）。如果有人知道如何解决此问题或对如何更改样式有更简单的建议，我将不胜感激！

【问题讨论】：

在所有输入中都使用 mysqli_real_escape_string 很好，这表明您已经考虑避免 SQL 注入，但我仍然建议您花时间学习如何使用准备好的语句。 MySQLi 支持准备好的语句，它们有很多好处。我还建议对输入进行一些验证，并且对来自不受信任来源的数据提供超过 1 层的保护也无妨
您需要在文字周围加上引号...== yes - == 'yes'
mysqli_real_escape_string 不使用默认字符集是不安全的。查看手册 -> php.net/manual/en/mysqli.real-escape-string.php

标签： javascript php html css mysql

【解决方案1】：

您需要在 com =='yes'

等引号中写上是或否

【讨论】：