Hi all,

I am setting up a registration form for a website im building.
When the user enters his/her information i would like to validate that the Username/Email aren't already in use.
At this point in time ive got my mind set on a function that runs 2 seconds after anything is typed into the Textbox.
This function works, it returns "Available" or "In use" when it should.
The problem is;
when the user begins to type, i would like my image (ajax-loader.gif) to appear, and when the script gives a result, i want the image to hide again.
but this only works ONCE.

My Code:
jQuery:

<script type="text/javascript">
$(document).ready(function() {
    $("#username").keyup(function(){
        $("#loading").show();
        setTimeout(function(){
            var entered_text = $("#username").val();
            validateUsername(entered_text);
            $("#loading").hide();
        }, 2000);
    });
});
function validateUsername(username)
{
    $("#username_valid").load("validate_username.php?Username=" + username);

}
</script>

HTML:

<tr><td>Username:</td><td colspan="2"><input id="username" type="text" name="username" /></td><td id="username_valid"><img id="loading" style="display:none;" src="ajax-loader.gif"/></td></tr>

(This is the only line of my HTML code that is relevant to my issue.)

PHP/MySQL:

<?php
$username = $_REQUEST['Username'];
$con = mysql_connect('*******', '******', '*******');
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }
mysql_select_db('users', $con);
$sql_query = mysql_query("SELECT 'username' FROM `users` WHERE `username`='" . $username . "'");
if(mysql_num_rows($sql_query)==1)
{
    echo "Sorry this name is already taken!";
}
else
{
    echo "This name is available!";
}

?>

I really stuck on this one.
Any help is appreciated.

Cheers, James

are there any JavaScript errors?

Also what is stopping me from entering the username as ' go drop table users -- or any other query that can complete screw up your database? You might want to think about sanitizing input or using stored procedures.

You might want to think about sanitizing input or using stored procedures.

Thanks, i actually did NOT think of this.
Im going to rethink my strategy for validating the form.