//HTML
<? // top of the page
if ($_REQUEST['var1'] !='' && $_REQUEST['var2'] !='') {
    $sq = "update table set clicked ='1' where row1 ='".$_REQUEST['var1']."' and row2 ='".$_REQUEST['var2']."'";
    $qu = mysql_query($sq) or die(mysql_error());

    header("Location: ".$_SERVER['PHP_SELF']."?var1=".$_REQUEST['var1']."&var2=".$_REQUEST['var2']);
}

// in the body tag
echo "<a href='index.php?var1=".$_REQUEST['var1']."&var2=".$_REQUEST['var2']."'>".$row['column1']."</a>";
?>

//Objective-C
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"http://website.com/dir/index.php?var1=%@&var2=%@", [loadString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding], [loadString2 stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]];
NSURLRequest *requestURL = [NSURLRequest requestWithURL:url];

[webView loadRequest:requestURL];