isset not working corrently

[msebar]

Sorry for the miss spell on correctly counldn't edit the title

 

I need to have the following 3 varibles checked to see if they are set and if not display an error saying "All fields need to be filled in."
My problem is that it's not working. Did I mess up on my if statement?

$tempneeded
$lowtemp
$gallons
 

<?php


$tempneeded = $_POST['tempneeded'];
$lowtemp = $_POST['lowtemp'];
$gallons = $_POST['gallons'];


     htmlspecialchars($tempneeded, ENT_QUOTES, 'UTF-8') . ' ' .  
     htmlspecialchars($lowtemp, ENT_QUOTES, 'UTF-8') . ' ' .  
     htmlspecialchars($gallons, ENT_QUOTES, 'UTF-8') . ' ' .  


$wgd = .5;
$tempdiff = $tempneeded - $lowtemp;
$wattsneeded = $tempdiff * ($gallons * $wgd);

if (!isset ($lowtemp,$tempneeded,$gallons))
{

echo "<b>All fields need to be filled in.</b>";

} else {
echo "<b>You will need a total of $wattsneeded watts to rasie your tempature $tempdiff degress, from $lowtemp to $tempneeded.</b></td></tr>";
}
?>

Edited October 8, 2014 by msebar

[ginerjm]

Why don't you test them before you start manipulating them?

 

Actually - they will be "set" when you assign those POST vars to them, or else you would get an error/notice that the post vars are not set.  So what you really want to test is the POST vars for being set and for being <> blank

Edited October 8, 2014 by ginerjm

[msebar]

The if statement doesn't work the rest of the code does. If I leave the fields blank coming in from the form it echo's the first statemnet. If I fill in the form the first statment still gets echoed and my results don't show. So my issue really is the else is not working

[ginerjm]

What do you mean by 'doesn't work'?  There's nothing wrong with the statements, altho the else echo seems odd with those closing html tags embedded.

 

do you have error checking turned on?

[Jacques1]

An empty form field does have a value, namely the empty string. So the isset() check always succeeds unless you manually remove the form field so that the parameter isn't present at all. If you want to check for empty fields, you need the empty() statement. This covers both missing parameters and empty parameters.

[msebar]

The empty statement worked. Thanks much

[Psycho]

The empty statement worked. Thanks much

 

You may want to consider trim()ing the values before that check. Otherwise, a value of only white-space characters (such as spaces) would cause empty() to return true.