update doesn't work

[BSC926]

I've been trying to update a table in my database triggered by an UPDATE button but somehow it doesn't work, whenever I change the values then click the update button, it just refreshes the values, no update/change happens..please help\[code\]<?phpsession_start();require_once("dbconnect.php");$webhost=$_GET["webhost"];$requesttitle=$_POST["requesttitle"];$requesturl=$_POST["requesturl"];$requestcap=$_POST["requestcap"];$requestdestype=$_POST["requestdestype"];$requestdbtype=$_POST["requestdbtype"];$deptname=$_POST["deptname"];$contactname=$_POST["contactname"];$contactnum=$_POST["contactnum"];$contactemail=$_POST["contactemail"];$startdate=$_POST["startdate"];$enddate=$_POST["enddate"];if(isset($_POST['button'])){$sql="update webhostrequest set requesttitle='$requesttitle', "; $sql.="requesturl='$requesturl', requestcap='$requestcap', "; $sql.="requestdestype='$requestdestype', requestdbtype='$requestdbtype', "; $sql.="deptname='$deptname', contactname='$contactname', "; $sql.="contactnum='$contactnum', contactemail='$contactemail' '; $sql.="startdate='$startdate', enddate='$enddate', recentact=now() where requestid='$id'";$result = mysql_query($sql) or die ("Error in editing item. ".mysql_error());}header("location: editwebhost.php?webhost=$webhost");exit;?>\[/code\]