Question

我制作了一个PHP表单并创建了这个错误处理脚本：

<?php 
    if(isset($_GET["alert"])) {
        $alert = $_GET["alert"];
        if($_GET["alert"]="nofilled") {
                echo "<div class='error'>You missed something!</div>";
        }
        elseif($_GET["alert"]="badpass") {
                echo "<div class='error'>Your passwords don't match!</div>";
        }
        elseif($_GET["alert"]="badusername") {
                echo "<div class='error'>Your username is too long!</div>";
        }
        elseif($_GET["alert"]="shortpass") {
                echo "<div class='error'>Your password is too short!</div>";
        }
        elseif($_GET["alert"]="takenusername") {
                echo "<div class='error'>That username is taken!</div>";
        }
        elseif($_GET["alert"]="takenemail") {
                echo "<div class='error'>That email already has an account attached to it!</div>";
        }
    }
?>

我尝试使用GET值'badpass'来运行它。出于某种原因，它回应了'nofilled'消息。

我正在学习这个，但我找不到解决方案。你能快速看一下，看看有什么不对吗？

Answer 1

您的问题发生是因为您使用的是'='而不是'=='（1是分配，2是比较）。但是，我建议使用以下方法，因为它更有效，更清洁：

if(isset($_GET["alert"])) {
    $alerts = array(
        "nofilled"=>"You missed something!",
        "badpass"=>"Your passwords don't match!",
        "badusername"=>"Your username is too long!",
        "shortpass"=>"Your password is too short!",
        "takenusername"=>"That username is taken!",
        "takenemail"=>"That email already has an account attached to it!"
        );

    echo "<div class='error'>". isset($alerts[$_GET['alert']]) ? $alerts[$_GET['alert']] : $alerts[$_GET['nofilled']]. "</div>";
}

Per @ Tun的正确评论，我在$alerts[$_GET['alert']])不存在的情况下添加了默认回退'nofilled'。

希望这有帮助！

Answer 2

这看起来更像是使用开关的情况：

<?php
if(isset($_GET["alert"])) {
  echo '<div class = "error">';
  switch($_GET['alert']) {
    case "nofilled": echo "You missed something!"; break;
    case "badpass": echo "Your passwords don't match!"; break;
    ...
    default: echo "An undetermined error ocurred"; break;
    }
  echo '</div>';
  }

甚至更好（更干），只需使用数组：

if (isset($_GET["alert"])) {
  $Errors = array(
    "nofilled" => "You missed something!",
    "badpass" => "Your passwords don't match!",
    ...
    );
  echo '<div class = "error">';
  if (array_key_exists($_GET['alert'], $Errors))
    echo $Errors[$_GET['alert']];
  else
    echo "An undetermined error ocurred";
  echo '</div>';
  }

Answer 3

默认为'nofilled'消息的原因是因为您在所有conditional statements =分配运算符而不是== >

=是assignment operator，而==是检查＆＃34; 是否等于＆＃34; comparison operator

<强>重写：

<?php 
    if(isset($_GET["alert"])) {
        $alert = $_GET["alert"];
        if($_GET["alert"]=="nofilled") {
                echo "<div class='error'>You missed something!</div>";
        }
        elseif($_GET["alert"]=="badpass") {
                echo "<div class='error'>Your passwords don't match!</div>";
        }
        elseif($_GET["alert"]=="badusername") {
                echo "<div class='error'>Your username is too long!</div>";
        }
        elseif($_GET["alert"]=="shortpass") {
                echo "<div class='error'>Your password is too short!</div>";
        }
        elseif($_GET["alert"]=="takenusername") {
                echo "<div class='error'>That username is taken!</div>";
        }
        elseif($_GET["alert"]=="takenemail") {
                echo "<div class='error'>That email already has an account attached to it!</div>";
        }
    }
?>

参考比较运算符手册：

http://www.php.net/manual/en/language.operators.comparison.php

Answer 4

=用于分配内容

==用于比较

在您的条件中使用==

 if(isset($_GET["alert"])) {
            $alert = $_GET["alert"];
            if($_GET["alert"]=="nofilled") {
                    echo "<div class=='error'>You missed something!</div>";
            }
            elseif($_GET["alert"]=="badpass") {
                    echo "<div class=='error'>Your passwords don't match!</div>";
            }
            elseif($_GET["alert"]=="badusername") {
                    echo "<div class=='error'>Your username is too long!</div>";
            }
            elseif($_GET["alert"]=="shortpass") {
                    echo "<div class=='error'>Your password is too short!</div>";
            }
            elseif($_GET["alert"]=="takenusername") {
                    echo "<div class=='error'>That username is taken!</div>";
            }
            elseif($_GET["alert"]=="takenemail") {
                    echo "<div class=='error'>That email already has an account attached to it!</div>";
            }
        }

Answer 5

=是一个赋值运算符。因此，$_GET["alert"]="nofilled"会将"nofilled"分配给$_GET["alert"]。相反，您应该使用===这是一个身份比较运算符。除非有充分理由，否则不应使用==进行比较。 ==执行自动类型转换，导致通常很难检测到的错误。由于转换，它也略微（但当然可以忽略不计）慢。

根据GET的值显示文本

5 个答案: