If isset $_POST

Question

I have a form on one page that submits to another page. There, it checks if the input mail is filled. If so then do something and if it is not filled, do something else. I don't understand why it always says that it is set, even if I send an empty form. What is missing or wrong?

step2.php:

<form name="new user" method="post" action="step2_check.php"> 
    <input type="text" name="mail"/> <br />
    <input type="password" name="password"/><br />
    <input type="submit"  value="continue"/>
</form>

step2_check:

if (isset($_POST["mail"])) {
    echo "Yes, mail is set";    
} else {    
    echo "N0, mail is not set";
}

Answer 1

Change it to this:

if (isset($_POST["mail"]) && !empty($_POST["mail"])) {
    echo "Yes, mail is set";    
} else {  
    echo "N0, mail is not set";
}

So $_POST is always set, but its content might be empty.

Since !empty() already checks whether the value is set, you can also use this version:

if (!empty($_POST["mail"])) {
    echo "Yes, mail is set";    
} else {  
    echo "N0, mail is not set";
}

Answer 2

Use !empty instead of isset. isset return true for $_POST because $_POST array is superglobal and always exists (set).

Or better use $_SERVER['REQUEST_METHOD'] == 'POST'

Answer 3

From php.net, isset

Returns TRUE if var exists and has value other than NULL, FALSE otherwise.

empty space is considered as set. You need to use empty() for checking all null options.

Answer 4

If you send the form empty, $_POST['mail'] will still be sent, but the value is empty. To check if the field is empty you need to check

if(isset($_POST["mail"]) && trim($_POST["mail"]) != "") { .. }

Answer 5

Add the following attribute to the input text form: required="required". If the form is not filled, it will not allow the user to submit the form.

Your new code will be:

<form name="new user" method="post" action="step2_check.php"> 
<input type="text" name="mail" required="required"/> <br />
<input type="password" name="password" required="required"/><br />
<input type="submit"  value="continue"/>

if (isset($_POST["mail"])) {
    echo "Yes, mail is set";    
}

Answer 6

You can simply use:

if($_POST['username'] and $_POST['password']){
  $username = $_POST['username'];
  $password = $_POST['password'];
}

Alternatively, use empty()

if(!empty($_POST['username']) and !empty($_POST['password'])){
  $username = $_POST['username'];
  $password = $_POST['password'];
}

Answer 7

Use !empty() instead of isset(). Because isset() will always return true in your case.

if (!empty($_POST["mail"])) {
    echo "Yes, mail is entered";    
} else {  
    echo "No, mail is not entered";
}

Answer 8

Maybe you can try this one:

if (isset($_POST['mail']) && ($_POST['mail'] !=0)) { echo "Yes, mail is set"; } else { echo "No, mail is not set"; }

---

Answer 9

<?php
    if(isset($_POST['mail']) && $_POST['mail']!='') {
        echo "Yes, mail is set";
    }else{
        echo "N0, mail is not set";
    }
?>

Answer 10

To answer the posted question: isset and empty together gives three conditions. This can be used by Javascript with an ajax command as well.

$errMess="Didn't test";   // This message should not show
if(isset($_POST["foo"])){ // does it exist or not
    $foo = $_POST["foo"]; // save $foo from POST made by HTTP request
    if(empty($foo)){      // exist but it's null
        $errMess="Empty"; // #1 Nothing in $foo it's emtpy

    } else {              // exist and has data
        $errMess="None";  // #2 Something in $foo use it now
      }
} else {                  // couldn't find ?foo=dataHere
     $errMess="Missing";  // #3 There's no foo in request data
  }

echo "Was there a problem: ".$errMess."!";

Answer 11

You can try this:

if (isset($_POST["mail"]) !== false) {
    echo "Yes, mail is set";    
}else{  
    echo "N0, mail is not set";
}

Answer 12

<form name="new user" method="post" action="step2_check.php"> 
  <input type="text" name="mail" required="required"/> <br />
  <input type="password" name="password" required="required"/><br />
  <input type="submit"  value="continue"/>
</form>

<?php
if (!empty($_POST["mail"])) {
    echo "Yes, mail is set";    
}else{  
    echo "N0, mail is not set";
}
?>

Answer 13

You can try,

 <?php

     if (isset($_POST["mail"])) {
            echo "Yes, mail is set";    
        }else{  
            echo "N0, mail is not set";
        }
  ?>

Answer 14

Lets Think this is your HTML Form in step2.php

step2.php

<form name="new user" method="post" action="step2_check.php"> 
    <input type="text" name="mail"/> <br />
    <input type="password" name="password"/><br />
    <input type="submit"  value="continue"/>
</form>

I think you need it for your database, so you can assign your HTML Form Value to php Variable, now you can use Real Escape String and below must be your

step2_check.php

if(isset($_POST['mail']) && !empty($_POST['mail']))
{
$mail = mysqli_real_escape_string($db, $_POST['mail']);
}

Where $db is your Database Connection.