Need help checking if $_POST filed is empty

[Beauford]

Sometimes the simplest things in PHP just baffle me:

 

I have a form with 12 fields. There are two fields that are optional.

 

If the user does enter something in these fields, I want to be able to check that and verify the information. If not, just move on with the rest of the script.

 

No matter what I do, even if nothing is entered in these fields, PHP thinks there is and tries to validate it. which screws everything up as there is really nothing there to validate.

 

I have tried if($_POST['value']) { do something }

I have tried if(!$_POST['value']) { do something }

I have tried if(isset($_POST['value'])) { do something }

I have tried if(!isset($_POST['value'])) { do something }

and a bunch of of stuff I was grasping at to get this to work.

 

This has got to be simple, but again, I have no clue.

 

The result I want is this. If there is a value, it has to be a number > than 0. Then I want to do a query on that number to make sure that it is in the DB. If it is, then the script continues, if not, an error is posted.

 

Thanks

 

B

[daveh33]

if (!$_POST['field-name']) {

 

// The field has no value

 

} else {

 

// The field has a value

 

}

[Beauford]

if (!$_POST['field-name']) {

 

// The field has no value

 

} else {

 

// The field has a value

 

}

 

Have tried that as per my posting, but I don't need to do anything if it is empty, so I need to check first to see if it has a value. Which for some reason always seems to, even if the user put nothing in the field.

 

thanks

[wildteen88]

You should do it like this

if(isset($_POST['field_name_here']) && !empty($_POST['field_name_here']))
{
    // field has a value
}

[Beauford]

You should do it like this

if(isset($_POST['field_name_here']) && !empty($_POST['field_name_here']))
{
    // field has a value
}

 

This just gets more ridiculous. Now it doesn't think the 0 is a value or isn't numeric - and bypasses the check. See test code below.

 

if(isset($_POST['pfor']) && !empty($_POST['pfor'])) {

if(is_numeric($_POST['pfor'])) {

if($_POST['pfor'] == 0) {

$q=$db->query("SELECT userid, username FROM users WHERE userid={$_POST['pfor']}");

if($db->num_rows($q) == 0) {

$error = 1;

}

}

else {

$error = 1;

}

}

else {

$error = 1;

}

}

[Ken2k7]

Well 0 is empty.

 

Try this -

         if(!empty($_POST['pfor']) && $_POST['pfor'] !== 0) {
            if(is_numeric($_POST['pfor'])) {
               if($_POST['pfor'] == 0) {
                  $q=$db->query("SELECT userid, username FROM users WHERE userid={$_POST['pfor']}");
                  if($db->num_rows($q) == 0) {   
                     $error = 1;
                  }
               }
               else {
                  $error = 1;
               }
            }
            else {
               $error = 1;
            }         
         }

[Beauford]

Well 0 is empty.

 

Try this -

         if(!empty($_POST['pfor']) && $_POST['pfor'] !== 0) {
            if(is_numeric($_POST['pfor'])) {
               if($_POST['pfor'] == 0) {
                  $q=$db->query("SELECT userid, username FROM users WHERE userid={$_POST['pfor']}");
                  if($db->num_rows($q) == 0) {   
                     $error = 1;
                  }
               }
               else {
                  $error = 1;
               }
            }
            else {
               $error = 1;
            }         
         }

 

Thanks for the info and the code, but it still doesn't work. and not to get into a long discussion, but to me 0 is NOT empty. It takes up space, bytes, memory, or whatever else to display it, and this is what I want to check for. The only time it should bypass the check is if there is nothing there. The user entered nothing. 0 is something. Can PHP not do this simple function?

 

 

[Ken2k7]

Well PHP's empty function treats 0 as empty.

 

Try this -

         if(!empty($_POST['pfor']) && intval($_POST['pfor']) !== 0) {
            if(is_numeric($_POST['pfor'])) {
               if($_POST['pfor'] == 0) {
                  $q=$db->query("SELECT userid, username FROM users WHERE userid={$_POST['pfor']}");
                  if($db->num_rows($q) == 0) {   
                     $error = 1;
                  }
               }
               else {
                  $error = 1;
               }
            }
            else {
               $error = 1;
            }         
         }

[allworknoplay]

What about checking for NULL?

 

$_POST['value'] == NULL

 

 

[Ken2k7]

What about checking for NULL?

 

$_POST['value'] == NULL

empty checks for that already.

[radi8]

Well it seems as though the following is invalid because the second test for 0 can never occur:

<?php
if(!empty($_POST['pfor']) && intval($_POST['pfor']) !== 0) {
            if(is_numeric($_POST['pfor'])) {
               if($_POST['pfor'] == 0) {
                  $q=$db->query("SELECT userid, username FROM users WHERE userid={$_POST['pfor']}");
                  if($db->num_rows($q) == 0) {   
                     $error = 1;
                  }
               }
               else {
                  $error = 1;
               }
            }
            else {
               $error = 1;
            }         
         }
?>

 

Try this instead:

<?php
if(isset($_POST['pfor']) && (is_numeric($_POST['pfor']) || intval($_POST['pfor']) == 0)) {
    if($_POST['pfor'] == 0) {
        $q=$db->query("SELECT userid, username FROM users WHERE userid={$_POST['pfor']}");
        if($db->num_rows($q) == 0) {   
            $error = 1;
        }
        else{
            // Record-set retrieved, do something totally cool here
        }
    }
    else {
        $error = 1;
    }
}
else {
    $error = 1;
} 
?>

[wildteen88]

PHP sees zero with two meanings an integer and a boolean (false). You should also note that all $_POST data are strings.

 

So if you want to see if the user only entered a zero in the field use

if($_POST['pfor'] == '0')

 

or type cast

$pfor = (int) $_POST['pfor'];
if($pfor === 0)

 

[Beauford]

Lets go back to the beginning. All I want to do is see if the user put something in $_POST['pfor'].

 

This could be a 'z', a 'q' a > a ? a 9 or the 0.  If the user has entered nothing then just move on with the rest of the script, if there is a value then it gets checked.

 

I just find it unbelievable that PHP can not handle this seemingly simple function.

 

thanks for all the input.

 

 

[Ken2k7]

         if(!empty($_POST['pfor']) || intval($_POST['pfor']) == 0) {
            if(is_numeric($_POST['pfor'])) {
               if($_POST['pfor'] == 0) {
                  $q=$db->query("SELECT userid, username FROM users WHERE userid={$_POST['pfor']}");
                  if($db->num_rows($q) == 0) {   
                     $error = 1;
                  }
               }
               else {
                  $error = 1;
               }
            }
            else {
               $error = 1;
            }         
         }

[Beauford]

This is how I believe I have got around this.

 

in the form I do this.

 

<td><input type='text' name='pfor' value=''></td>

 

For the check I do this.

 

if($_POST['pfor'] != "") {

    Check the rest of it

}

 

Not my first choice, but workable.

 

Thanks again.