PHP 表单验证在提交前显示错误

Question

我正在制作一个 PHP 和 MySQL 应用程序来练习我对编程的新爱好。我有一个登录脚本； HTML 格式如下:

<form action="<?php echo $_SERVER["PHP_SELF"]; ?>" method="post">

            Username:

                <input type="text" name="username" maxlength="60"><br />



            Password:

                <input type="password" name="password" maxlength="60"><br />



           Confirm Password:

                <input type="password" name="password_confirm" maxlength="60"><br />


                <input type="submit" name="submit" value="Register"><br />

         </form>

这继续进入 PHP 表单验证器:

<?php

$username_original = $_POST["username"];
$password_original = $_POST["password"];
$password_confirm_original = $_POST["password_confirm"];

       //This makes sure they did not leave any fields blank 

function FieldComplete($user, $password, $password_confirm) {
    if (!isset($user, $password, $password_confirm) &&
        $user && $password && $password_confirm == "" || " ") {
        $field_confirm = false;
    } else {
        $field_confirm = true;
    }


    if ($field_confirm == true) {
        echo "";
    } else {
        echo "You did not complete all the required fields.";
    }
}

FieldComplete($username_original, $password_original, $password_confirm_original);

?>

我意识到为此创建一个函数可能看起来有点无用，但它已经接近我想要的结果了。

但是，此代码显示错误“您没有完成所有必填字段。”在加载页面时。我只希望在他们按下注册按钮但仍然有空白字段时显示该错误。

非常感谢任何建议或帮助。感谢 StackOverflow 社区!

Answer 1

如果你只想在提交按钮时运行 php 代码，那么你需要在页面顶部检查它

if(isset($_POST["submit"]))
{
   //form has been submitted
   //do validation and database operation and whatever you need
} else {
  //form has not been submitted
  //print the form
}