checkbox question with php
<p>My question is when user click on checkbox, then user is activated. this code is working fine. But when user again click on  uncheckbox, then again user de-activated. How to do that? here is my working code.</p>

<p>Activate user when user click on checkbox</p>

<pre><code>if($_GET['doAction'] == 'Activate') {
    if(!empty($_GET['q'])) {
        $userid = $_GET['q'];
        $conn = db_connection();
        $query = "UPDATE user SET activate = '1' WHERE userid = '".$userid."' ";
        $result=$conn-&gt;query($query);
    }
}
</code></pre>

<p>here is my checkbox</p>

<pre><code>&lt;input type="checkbox" name="app" onchange="callUser(this.value,doAction.value);" value="&lt;?php echo $userid;?&gt;" &lt;?php if($row['approved'] == '1'){ echo "checked=\"true\""; }?&gt;/&gt;
&lt;input type="hidden" name="doAction" id="doAction" value="Approved" /&gt;
</code></pre>

<p>thanks you so much. :-) 
EDIT-> Here is calluser() Function</p>

<pre><code>&lt;script type="text/javascript"&gt;
function callUser(str,action,third)
{
 var xmlhttp;    
if (str=="")
{
document.getElementById("txtHint").innerHTML="";
return;
}
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari 
  xmlhttp=new XMLHttpRequest();
}
else
 {// code for IE6, IE5
 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
 }
xmlhttp.onreadystatechange=function()
 {
if (xmlhttp.readyState==4 &amp;&amp; xmlhttp.status==200)
 {
 document.getElementById("txtHint").innerHTML=xmlhttp.responseText;

}
}
xmlhttp.open("GET","adminPanel.php?    q="+str+"&amp;doAction="+action+"&amp;app="+third,true);
    xmlhttp.send();
}
 &lt;/script&gt;
</code></pre>

<p>Here is screenshot <a href="http://i.stack.imgur.com/MpQfC.png" rel="nofollow">http://i.stack.imgur.com/MpQfC.png</a></p>
