php echo and $_POST why this is incorrect?
<pre><code>&lt;?php
if(array_key_exists('sub1',$_POST))
{
echo"&lt;input type='Checkbox' name='negin'  value='yes' checked /&gt;";
echo $_POST['negin'];
}
?&gt;

&lt;html&gt;
&lt;head&gt;
&lt;body&gt;
&lt;form method="post"&gt;
&lt;input type="submit" name='sub1' value="sub"/&gt;
&lt;/form&gt;
&lt;/body&gt;
&lt;/head&gt;
&lt;/html&gt;
</code></pre>
