Variable not empty, when it should be empty?
<pre><code>&lt;?php
$a = $_POST['a'];
$b = $_POST['b'];
$c;

if(is_numeric($a) &amp;&amp; is_numeric($b)){
echo "string";
exit();
}

if(!is_numeric($a) &amp;&amp; !is_numeric($b)) {
echo "string";
exit();
}

if(isset($a)){
$resultat=$b*2.54;
echo "string " . $c . " string";
exit();
}

if(isset($b)){
$resultat=$a/2.54;
echo "string " . $c . " string";
exit();
}
?&gt;
</code></pre>

<p>I start by checking wether form field 1 &amp; 2 hold nummeric values, then i check if both hold values.
That works fine, but when i get down to the second part, it never gets past the first "if" it always sees "a$" as set ... </p>

<p>Do i have to use case? or ?</p>
