PHP在未调用时显示else“错误”

Question

我的php代码有问题。

我不希望显示else echo "Check it again!";，除非他们在表单(输入框)中输入了一些数据，而表单是无效的。但是当我加载页面时，它会在框的上方显示错误。

<?PHP
if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
    mysql_query("INSERT INTO newsletter (email) VALUES('$email')") or die(mysql_error());
        echo 'You have registered your E-Mail address to our database! You will now receive regular updates on the progess!';
    }else{
        echo "Check it again!";
}
?>

<form name="newsletter" method="post" action="<?PHP $_SERVER['PHP_SELF']?>">
<input type="text" name="newsletter" id="newsletter">
<input type="submit" value="SUBMIT!">
</form>

Answer 1

试试这个:)

<?PHP
if($_SERVER["REQUEST_METHOD"]=="POST"){
    if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
        mysql_query("INSERT INTO newsletter (email) VALUES('$email')") or die(mysql_error());
            echo 'You have registered your E-Mail address to our database! You will now receive regular updates on the progess!';
        }else{
            echo "Check it again!";
    }
}
?>

而不是

<?PHP

 if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
    mysql_query("INSERT INTO newsletter (email) VALUES('$email')") or die(mysql_error());
    echo 'You have registered your E-Mail address to our database! You will now receive regular updates on the progess!';
    }else{
      echo "Check it again!";
    }
}

?>

编辑背后的逻辑:我们将检查电子邮件或打印“再检查一次！”只有在提交表单的情况下。现在，如果我们不检查表单是否已提交，或者这是第一次加载(或简单刷新)页面，则将发生插入或错误显示。我们不希望出现这种情况:)

Answer 2

这只是@MuhammedHedayet答案的另一种选择，我更喜欢这种风格，只在需要的时候检查它。两者都应该能完美地工作：

<?PHP
if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
    mysql_query("INSERT INTO newsletter (email) VALUES('$email')") or die(mysql_error());
        echo 'You have registered your E-Mail address to our database! You will now receive regular updates on the progess!';
    } else if ($_SERVER["REQUEST_METHOD"]=="POST"){
        echo "Check it again!";
}
?>

<form name="newsletter" method="post" action="<?PHP $_SERVER['PHP_SELF']?>">
<input type="text" name="newsletter" id="newsletter">
<input type="submit" value="SUBMIT!">
</form>