value of input from PHP postback
<p>I have the following code:</p>

<pre><code>&lt;form&gt;
   .............
    &lt;?php
    if (!isset($_FILES['before']['name'] || !isset($_FILES['after']['name']) 
        echo '&lt;input type="submit" value="Show Image"&gt;'
    else 
        echo '&lt;input type="submit" value="Upload"&gt;'
    ?&gt;
&lt;/form&gt;
</code></pre>

<p>in my postback how do I check whether it's one or the other?</p>
