PHP isset函数未正确检查

单击按钮时。我想使用register_按钮从表单中获取值。但是，它没有进入if子句

在if语句中，我无法检查表单中键入的任何内容。 是否有其他选项可以从表单中检索数据，或者我是否犯了一些错误

var\u dump$\u POST返回

代码：

---

它进入了第一个if语句。您可以看出这一点，因为当您使用var_dump$_POST时，在转储输出之后会得到无效的文本格式。这意味着它将进入页面下一步的else语句中，在那里您有echo Invalid format；。因此，实际上是您的筛选变量if语句失败了。

请不要在任何人回答后编辑您的问题 您不会检查查询是否成功。 如果要过滤变量，最好是直接进行过滤 您忘了在字符串后的查询中添加逗号

请尝试下面的方法

<?php
$fname = "";
$lname = "";
$em = "";
$em2 = "";
$password = "";
$password2 = "";
$date = "";
$error_array = "";
if (isset($_POST['register_button'])) {
    $fname = strip_tags($_POST['reg_fname']);
    $fname = str_replace(' ', ' ', $fname);
    $lname = $_POST['reg_lname'];
    $lname = str_replace(' ', ' ', $lname);

    $em = $_POST['reg_email'];
    $em = str_replace(' ', ' ', $em);

    $password = strip_tags($_POST['reg_pass']);
    $password2 = strip_tags($_POST['reg_pass2']);

    $date = date("Y-m-d");
    // No need to use if
    $em = filter_var($em, FILTER_VALIDATE_EMAIL);
    /// $con = mysqli_connect("localhost", "user", "pass", "dbname");
    /// using if to be sure query success
    if ($e_check= mysqli_query($con, "SELECT email FROM users WHERE email='$em'")) {

        $num_rows= mysqli_num_rows($e_check);
        if ($num_rows> 0) {
            echo "Email already in use";
        } else {
            /// here your insert query

        }
    }
    else
    {
        echo "No query ";
    } 
    if(strlen($fname) >25 || strlen($fname)< 2 )
    { 
        echo "Your first name must be at least 2 char and maximum 25 char "; 
    }
}

---

为什么要使用登记按钮作为支票？为什么没有一个字段是必需的？

这些字段在元素中吗？var_dump$_POST告诉您什么？是的，它们在元素中。var\u dump$\u POST返回数组6{[reg\u fname]=>string1 a[reg\u lname]=>string3 asd[reg\u email]=>string5ad@ad[reg_pass]=>string4 dasd[reg_pass2]=>string5 sadsa[register_button]=>string8 register}无效格式编辑您的问题以包含此信息。您也不应默默更改用户密码。如果我想用myword作为密码，我应该可以，不是吗？最后但并非最不重要的一点是，您应该使用来访问数据库。不要更改或过滤密码。这是不合理的，你让他们很脆弱。使用密码哈希API对密码进行哈希和验证。由于键入错误（如缺少或额外的}）而导致的问题不在SO主题中。不要回答，而是将问题标记为离题。这不是打字错误造成的。他的代码运行良好。

$fname = "";
$lname = "";
$em = "";
$em2 = "";
$password = "";
$password2 = "";
$date = "";
$error_array = "";

if (isset($_POST['register_button'])) {

    $fname = strip_tags($_POST['reg_fname']);
    $fname = str_replace(' ', ' ', $fname);
    $lname = $_POST['reg_lname'];
    $lname = str_replace(' ', ' ', $lname);

    $em = $_POST['reg_email'];
    $em = str_replace(' ', ' ', $em);

    $password = strip_tags($_POST['reg_pass']);
    $password2 = strip_tags($_POST['reg_pass2']);

    $date = date("Y-m-d");

    if(filter_var($em, FILTER_VALIDATE_EMAIL)){
        $em = filter_var($em, FILTER_VALIDATE_EMAIL);

        $e_check = mysqli_query($con, "SELECT email FROM users WHERE email='$em");

        $num_rows = mysqli_num_rows($e_check);

        if(num_rows > 0){
            echo "Email already in use";
        }
    }else {
        echo "Invalid format";
    }

    if(strlen(fname)>25 || strlen(fname)<2 ){
        echo "Your fi";
    }
}

<form method="post" action="index.php">

<input type = "text" name="reg_fname" placeholder="First Name"       required>
<br>
<input type = "text" name="reg_lname" placeholder="Last Name" required>
<br>
<input type = "email" name="reg_email" placeholder="Email" required>
<br>
<input type = "password" name="reg_pass" placeholder="Password" required>
<br>
<input type = "password" name="reg_pass2" placeholder="Confirm Password" required>
<br>
<input type = "submit" name="register_button" value="Register">

</form>

<?php
$fname = "";
$lname = "";
$em = "";
$em2 = "";
$password = "";
$password2 = "";
$date = "";
$error_array = "";
if (isset($_POST['register_button'])) {
    $fname = strip_tags($_POST['reg_fname']);
    $fname = str_replace(' ', ' ', $fname);
    $lname = $_POST['reg_lname'];
    $lname = str_replace(' ', ' ', $lname);

    $em = $_POST['reg_email'];
    $em = str_replace(' ', ' ', $em);

    $password = strip_tags($_POST['reg_pass']);
    $password2 = strip_tags($_POST['reg_pass2']);

    $date = date("Y-m-d");
    // No need to use if
    $em = filter_var($em, FILTER_VALIDATE_EMAIL);
    /// $con = mysqli_connect("localhost", "user", "pass", "dbname");
    /// using if to be sure query success
    if ($e_check= mysqli_query($con, "SELECT email FROM users WHERE email='$em'")) {

        $num_rows= mysqli_num_rows($e_check);
        if ($num_rows> 0) {
            echo "Email already in use";
        } else {
            /// here your insert query

        }
    }
    else
    {
        echo "No query ";
    } 
    if(strlen($fname) >25 || strlen($fname)< 2 )
    { 
        echo "Your first name must be at least 2 char and maximum 25 char "; 
    }
}