As I am working on Mssql rather than Mysql, I have to try and re-write most of the functions in this script.

I wanted to simplify the check availability process on my username field within registration because mssql doesnt support some of the same commands.

At present I have gotten this far:
<p>Username<span class="required">*</span></p>
			<input name="user_name" type="text" id="user_name" class="required username" minlength="5" > 
              <input name="btnAvailable" type="button" id="btnAvailable" 
			  onclick='$("#checkid").html("Please wait..."); $.get("checkuser.php",{ cmd: "check", user: $("#user_name").val() } ,function(data){  $("#checkid").html(data); });'
			  value="Check Availability"> 
			    <span style="color:red; font: bold 12px verdana; " id="checkid" ></span>

include 'dbc.php';

foreach($_GET as $key => $value) {
	$get[$key] = filter($value);

$user = $get['user'];

if(isset($get['cmd']) && $get['cmd'] == 'check') {

if(!isUserID($user)) {
echo "Invalid User ID";

if(empty($user) && strlen($user) <=3) {
echo "Enter 5 chars or more";

$rs_duplicate = mssql_query("select count(*) as total from Consumer where user_name='$user' ") or die();
list($total) = mssql_fetch_row($rs_duplicate);

	if ($total > 0)
	echo "Not Available";
	} else {
	echo "Available";

But on clicking this, it gives me:
Fatal error: Call to undefined function mssql_query() in C:\HostingSpaces\JoPoTa\\wwwroot\checkuser.php on line 25

and I am not too sure what the problem is.

Is there anyway of getting this to work? And if not, is there a way of simplifying the onclick function to just say "when clicked, check the database and return taken or available" without any of this please wait stuff.

Thanks, Adey