$_POST not working in PHP
<pre><code>&lt;html&gt;
&lt;head&gt;&lt;title&gt;HEllo&lt;/title&gt;&lt;/head&gt;
&lt;body&gt;
&lt;input type="text" name="id"&gt;
&lt;input type="text" name="name"&gt;
&lt;input type="text" name="address"&gt;
&lt;input type ="submit" name = "s" value = "Employee"&gt;
&lt;?php
$link =mysql_connect('localhost','root') or die("Failed");
mysql_select_db("gagan",$link) or die("database not exists");

if($_POST['s']=="Employee")
{
print "g";
$id = mysql_real_escape_string($_POST['id']);
$name = $_POST['name'];
$address = $_POST['address'];
print "hi";
$update = "update emp set name = $name, address=$address where id = $id";
$result = mysql_query($update,$link);
print "Hello";
if($result)
{
    print "Updated";
}   
else{   
    print "$update";
}
}

?&gt;
&lt;/body&gt;
&lt;/html&gt;
</code></pre>

<p>When i run this code it produce an notice and the above code is not working.</p>

<blockquote>
  <p>Notice: Undefined index: s in C:\wamp\www\1.php on line 12</p>
</blockquote>

<p>What's the problem in my code can anybody tell me?  </p>
